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9913680 1996-1998 Vol. II ATV Service Manual Chapter

1. 20 70 mm Limit 059 1 5 mm 059 1 5 mm Std 0016 0031 040 080 mm 0016 0031 040 080 mm Limit 0059 15 mm 0059 15 mm Std 0012 0028 030 070 mm 0012 0028 030 070 mm Limit 0059 15 mm 0059 15 mm Piston ring installed gap Piston Ring Standard clearance piston ring to ring groove Top ring Second ie Connecting Connecting rod small end ID 9058 9063 23 007 23 020 mm 9058 9063 23 007 23 020 mm Rod Connecting rod small end radial clear 0003 0010 007 026 mm 0003 0010 007 026 mm ers 0020 05 mm 0020 05 mm Connecting rod big end side clearance 0039 0256 1 65 mm 0039 0256 1 65 mm 0315 80 mm 0315 80 mm Connecting rod big end radial clear 0004 0015 011 038 mm 0004 0015 011 038 mm AE 0020 05 mm 0020 05 mm Crankshaft Crankshaft runout limit 0024 06 mm 0024 06 mm KEY Std Standard OS Oversize ID Inner Diameter OD Outer Diameter Mag Magneto Side PTO Power Take Off Side Polaris Industries Inc 3 On 5 98 ENGINE Cooling System 5 98 Radiator Thermostat EH42 50PL Cylinder Head Vent hole inside cap i liner must be freeof SDSIMGUON ss Cy Locate hole on inside of Fe radiator below filler neck of N Hole must be clear or i bleeding will be difficult mme f i Fan Switch F
2. HR J haer i ath rath Ha alll mit i Hi pae HR maa RL LA i j H Ht olaris Industries Inc ENGINE EC25PF EC28PF Engines Assembly Cont 2 Apply Loctite No 518 Gasket Eliminator to both sides of the cylinder base gasket Install the base gasket and cylinder Torque the cylinder base nuts in 3 steps to 28 ft Ibs 3 9 kg m Install the head gasket and head Torque nuts to 20 ft Ibs 2 8 kg m following pattern on page 3 2 When installing base gasket use gasket eliminator no 518 on both sides of the base gasket Oil check valve should release as specified below ee ee iat E EE k Stator Plate Timing einstall Stator plate and align timing Marks eee Retard l Center the mark 2 Reinstall flywheel with stator plate attaching screw hol 3 Reinstall magneto housing 4 Torque flywheel bolt to 44 62 ft Ibs 6 08 8 57 kg m 5 Reinstall recoil starter assembly N Coil must be installed with numbers out Use Sealer 6 Seal wire harness grommet to crankcase using RTV silicone sealant 7 Refer to electrical section of this manual for starter motor inspection Reinstall starter motor 5 98 3 18 Polaris Industries Inc ENGINE EC25PF EC28PF Engines Installation 1 The engine can be reinstalled into the frame and secured The oil pump and carburetor can also be assembled onto the engine Bleed the oil pump of trapped air by loosening the bleed
3. If you install the metal drive gear without the thrust washer you will not be able to achieve the proper drive gear end play as outlined below Refer to the Illustration on page 3 21 250 300 Models Refer to Illustration on following page 1 Measure distance from pump shoulder to pump mounting flange Record this measurement Example 3 9mm 2 Lubricate and install pump drive gear thrust washer pump drive gear and bushing into crankcase Make sure parts are completely seated 3 Measure the distance from the pump bushing to the crankcase pump seating surface Record this measurement Example 4 8mm 4 Subtract the measurement recorded in step 1 from the measurement recorded in step 3 See example below right The difference between these two measurements is the end play the pump bushings will have without shims Add shims to adjust end play to 008 024 2 6 EXAMPLE 4 8 mm 9 Spacer shim part numbers PN 3083671 15 mm 006 PN 3083672 3mm 012 PN 3083673 6mm 024 3 7mm Total thickness of shims required a 2 6mm Target clearance 5 98 3 20 Polaris Industries Inc Assembly Oil Check Valve Testing 250 400 The oil pump check valve on the EC25PF engine must be tested by applying 2 7 PSI of pressure to the line spigot of the check valve Use a Mity Vac PN2870975 or similar tester The valve should release between 2 and 7 PSI The check valve is located on the cylind
4. balancer drive gear and crankshaft main bearing area Tang Outward 5 Install the piston on the connecting rod with the arrow facing the magneto RH end of the crankshaft The piston pin should be a push fit in the piston 6 Install the other circlip with the gap facing up or down and tang outward See Caution with step 3 above Push the piston pin in both directions to make sure the clips are properly seated in the groove Polaris Industries Inc 3 79 7 96 ENGINE EH42PL EH50PL Engine svan adi ROTH Habe sse m b O nt Ee sre i a ei Bt A ni iani j j J Hata 7 Place the dowel pins in the crankcase and install a new cylinder base gasket 4 ist wd i in on has A364 9 a ited Pbidsdesd Bt TORE iH TEES eh mn wae 5 i ERTAIN Cylinder Installation veer er ts aeeri tess Position the piston support block PN 2870390 aoe ne beneath the piston skirt to support the piston during cylinder installation gga LH 2 Apply clean engine oil to the ring compressor Snap n PN RCL3O and install the compressor following i ae ia SUSUR Sa SSS Seca saaien COPT IRPTTIE OIREET OSIRE TEIRETET METTER 5 i AHAHA II IARAA AABE H f Hug PREOTEO dba a8 manufacturers instructions CAUTION Make sure a a f the oil control ring upper rail tab is positioned properly in the notch of the piston Verify all ring end gaps are oa lt a correctly located cee a O othe a Sa ii
5. lii i Polaris Industries Inc 3 45 7 96 ENGINE EH42PL EHS50PL Engine Engine Disassembly Cont 4 Measure O D of rocker shaft Inspect it for wear or damage 5 Measure D of each rocker arm 6 Measure I D of both rocker arm shaft supports and visually inspect surface 7 Inspect rocker adjuster screws for wear pitting or damage to threads of the adjuster or locknut Replace all worn or damaged parts NOTE The end of the adjuster screw is hardened and cannot be ground or re faced 7 96 3 46 Polaris Industries Inc ENGINE EH42PL EH50PL Engine Engine Disassembly Cont Camshaft Removal i AO w 1 Remove camshaft sprocket inspection cover i a 2 Loosen three camshaft sprocket bolts 3 Remove thermostat housing and thermostat Note the location of the air bleed holes in the thermostat Upon reassembly the thermostat bleed holes should be positioned next to the holes for the thermostat cover bolts 4 Remove camshaft end cap and O Ring 5 Place a clean shop towel in the area below cam chain sprocket and remove sprocket retaining bolts 6 Slide camshaft inward to allow removal of cam sprocket and remove sprocket from camshaft and chain 7 Secure cam chain with a wire to prevent it from falling into the crankcase 8 Inspect cam sprocket teeth for wear or damage Replace if necessary 9 Slide camshaft out the PTO side of the cylinder head Polaris Industries Inc
6. 7 Bend back retainer tabs on three screws at the front of the inner cover and remove screws and retainer plate 8 Loosen three inner cover retaining bolts at the rear of the cover only enough to allow cover removal 9 Remove cover NOTE Do not lose spacers or spacer retaining O rings located on the inside of the inner cover Polaris Industries Inc 3 39 7 96 ENGINE EH42PL EHS50PL Engine Removal Cont Recoil Stator Removal NOTE Removal of the recoil flywheel and stator assembly will allow additional clearance for engine removal Remove e Recoil housing bolts and housing e Starter drive assembly Note the thrust washer located at the rear of the drive mechanism Flywheel nut and washer 1 Install flywheel puller and remove flywheel CAUTION Do not thread the puller bolts into the flywheel more than 1 4 63 cm or stator coils may be damaged 2 Mark or note position of stator plate on crankcase 3 Remove bolts and carefully remove stator assembly being careful not to damage the crankshaft bushing or oil seal on the stator plate 4 Wrap stator in a shop towel and secure stator out of the way on top of frame a Amy 5 Remove oil passage O Ring 6 Place a shop towel in the cam chain area and over crankshaft oil passage 7 Remove transmission linkage rods from shift selector and secure out of the way 8 Remove PVT air intake duct 9 Disconnect coolant temp sender wire 7 96 3
7. PEETEEEETEEEEEEEEEEEEEEEEEEEEEEEEEEEREEEEE PAALLA He dadi Hinn th PETTEE TIETEET mod ATTS Brreceesaaseeeetrirsest ir retrt HAA ni RTE NTT ICE TCE a tis der oH RMIT S1 Hide aynan nai PERT St raed ENGINE EC25PF EC28PF Engines A AL ie i PINT shy TTT ea Mab that fon A ELETTI pin aE H CETELE fetes eeited ts iH Mesbossedientatsrsdite itty ss rer dee erresity SirsereaRer etree ay SST TCR t Habba dda goa dda toreet Testreretra eet APES doe Tian a HABLA T Eva d ey Presses TST it stosnrerseretaiereerierarri trees babs ONT LAL iaBus AL BRADRPBRSBSSL I BERGESOSUBEBEABEABRBS BEA BANANARAMA SEDI da nett AAAA ittee teratai itt ern RiR ENO A PMT dane FYOSEEESEREEITEREOO OEE ERI OREO REE RI ORO EE EERIE RTE RIOT T zi 4b crates Crests with TTT SORCSRESTENT i this nth eetri an hiketan natina iauts ihhh PSEMBOABE dnnt IANA ANAIA ANA LIANDRA I PAIPA LAPIIPOPPI APAAPA PAAAPPAPRAPHANI AARIA IN AMARNAN AINA BE CERT SUAS Aes sdsads snaps dete Hd TRI TSSP PSPC ERPOD SC RE STRSTR sha PETTY ern eabeeeeteeeet sad iantbey date fara Hdd adaatee ns UeH ts teas tROORRAGECADRRABEAPMBEE SBBEG HABER t TASTES irre Baten ae SSIS AAAA i t AAAAAAAAAAAA AAAA AALA AAAA AAAA AAAA HAAA AAAA ALAA AAAA ET i ai itt mAN resister stort it learn ttt PERRIER n 4 him ay Pisida AAH etree SEPERNI tie aui HAMN
8. Polaris Industries Inc 3 97 7 96 ENGINE Piston Damage Checklist Piston Damage Checklist 2 Stroke Engines Some items may not apply to all engines e Oil tank empty oil wrong type or contaminated e Oil filter restricted Oil pump inoperative drive gear cable pump oil check valve restricted or faulty e Lean carburetion or oil delivery due to Vent lines pinched kinked or restricted carburetor oil tank fuel tank etc Restricted oil or fuel passages incorrect jetting for altitude temperature e inoperative fan or low fan RPM check fan motor amp draw should be less than 6 5 amps low bat tery fan switch or connections wiring e Cooling system cooling fins radiator fins restricted air flow obstructed e Incorrect piston to cylinder clearance e Air leaks in intake tract air intake ducts mounting flange damaged or loose e Foreign material ingestion e Aijrin oil pump lines e Airin cooling system low coolant level e Poor fuel quality e Restricted exhaust e Incorrect ignition timing e Spark plug heat range incorrect e Fan blade incorrectly installed or damaged e Air box carburetor or exhaust modified 5 98 3 98 Polaris Industries Inc
9. Rea art en P MAAE EA LETITI ETITI EE EEIEIEE TSE COC TANE EEREN Briss ee Oda Mea ay Vise e HGH UAINE EENEN Tbrtioneeettgeeeentsteoapente Pies adda rptdatvameed abs g4eb PAA 655s AEEES APPA DTS eee 1 OR HIERIE AAAA AR a a a a I RT SIRTT IRATON tyr 4 RRRA inin p Wiad be me EAIA g Was aren pet Tittirateedty it PAPRATI TTIE REETEERR A im mo Hey vubunyi EERTE TEEN TERETERE ERIR AREAN BM beat rn voy Tb va g H POETETO IRROTA ERT NAT IRETE Wey a feat Se a daniy A n F TEEEEETE STEIERT IRRT INTRET AHS estan ad SOE TREES SETS RET TTT eT TN H h RSM AHIA INPA HA BABNA ANMANN Mi Hinne aeti uy Soe en Bon hte tav te i AAR Aa SAY H Se a STS OAT at y ay rae i AARAA Sat AAN CRTC Sit St Sree ne ee hin MACOMHAMB Mis siatideptentercctccy ene ESET TT y istin ABABAB I EAIBARA NA AAA AIEA AA EA A Perens H raet Breton ast CPPS RENE EM Mn ROR NY ST TETTTI g r aH it 4 Re at aa STE j ihaw g KEENT OIRT eres HARAR hoa LEENTERREEER 7 nt ahdin H vats Tae aa Beds tsa basis a mt Tries Rn HoN ant tte lagi n fi MEN l wet n H A h HLH Ae Wess ARAARA HANAH ABPAPEPHA i ii 1PAn ison ireuisrert ist 1 AAE IENEN LEIAR IRA AAAA A ana adasa AN ERE ii 1 cE hit if y PRT Shere i pitty ttt it PREJETE a diji j 7 96 Polaris Industries Inc ENGINE EH42PL EH50PL Engine Assembly Cont 6 P u sh th e cyli n d e r d OWNW a r
10. 3 47 7 96 ENGINE EH42PL EH50PL Engine Engine Disassembly Cont Automatic Compression Release Removal Inspection NOTE The automatic compression release mecha nism can be inspected and serviced without removin the camshaft from the cylinder head The actuator ba in the camshaft is not replaceable Replace the cam shaft as an assembly if the actuator ball is worn or dam aged PAPA TPXEPREXERIE ORE E OREO OREELIC REO REOECO OIE TACLEO TEER RE RE RAO EEE gre ee are eo eee eae throughout the entire range of rotation The spring X ao ie hold the shaft weight against the stop pin E La i A In this position the actuator ball will be held a o outward in the compression release mode a i i at _ o eee setts ida sst ty rst CSEPI ETERA resetea MAIA MA ds HHHPH SRIStTSEMRE NT ATTORI ttr PEII ETETETT AN dade ad ats 2 Remove release lever shaft and return spring no N o CIETIE SITS PETAR d Sar ON Inspect shaft for wear or galling ORTH ed 4 Teter AUT TERTIT ITNE He abd Sei seey ti ru Stitt Ea eRe Bak rikit ai F 4 H RN PH H Bittern a Ri ROTM Brien H Hih th mihn iaaii Ahna IL it it i EVYFs Sas ssbinty artt Inspect lobe on end of release lever shaft and a ee vm ae actuator ball for wear and replace if necessary sii stented bet pypnecsndvanatd dena n sabananeesoesseertsavenecunbasseesssoeeiiaes ins nirt DPAP A IA MAADAM L TEILE INAID DAOIN PSPs PERERIN
11. 518 Gasket Eliminator or 3 Bond 1215 to the camshaft end cap and install using a new O Ring Check all cam timing marks to verify proper cam timing and install the cam chain tensioner body with a new gasket After tensioner installation rotate engine at least two revolutions and re check marks timing 3 85 Single TDC Mark Aligned 7 96 ENGINE EH42PL EH50PL Engine Assembly Method 2 Camshaft Timing Using Flywheel TDC Mark Crankshaft to Camshaft Centerline Pas Sprocket Alignment Pin AS fee Single TDC Mark Aligned TDC Mark Rotation Do Not Use Advance Marks Recoil Housing Timing inspection Hole 7 96 3 86 Polaris Industries Inc ENGINE EH42PL EH50PL Engine Assembly Cont Cam Chain Tensioner Installation 1 Release the ratchet pawl and push the tensioner plunger all the way into the tensioner body 2 Install the tensioner body with a new gasket and tighten the bolts 3 Install the spring new sealing washer and tensioner plug 4 Slowly rotate engine two to three revolutions and re check cam timing NOTE Plated links will not align after engine is rotated Check crankshaft position by aligning dot on sprocket with crankcase projection or TDC mark if flywheel is installed Use cam sprocket locating pin see Timing Method 2 to check camshaft position Stator Flywheel and Starter Drive Installation NOTE The stator flywheel starter drive and
12. Lube PN 2870510 or low temperature grease Polaris Industries Inc 3 91 ENGINE Sealed Recoil jC 10 96 ENGINE Sealed Recoil Recoil Assembly Cont 1 10 11 Route rope through guide bushing and into reel Tiea secure knot in end of the rope Wind rope counterclockwise onto the reel as viewed from ratchet side of reel as shown Lock rope into notch on outer edge of reel Apply a small amount of Polaris low temp grease or equivalent to the center post of the housing and the bushing Install reel into housing making sure the spring drive tab on the reel engages the spring and the reel is fully seated in the housing Apply downward pressure on the reel and rotate counterclockwise approximately 6 turns to pre wind the spring Continue rotating counterclockwise until rope on outer edge aligns with rope guide bushing Release rope from notch and allow reel to rewind completely If more pre wind is required place rope in notch and add additional turns of pre wind Install ratchet pawl and return spring Reinstall friction plate NOTE The friction plate must be positioned with both end tabs of the friction spring on the drive side of the ratchet Torque friction plate retaining bolt to 5 6 ft Ibs 69 828 kg m Reinstall recoil housing using a new gasket Seal stator wire harness grommet with RTV silicone 10 96 3 92 Mtt ttit tiiti Polaris Industries Inc ENGINE Spark Plug Foulin
13. and ee a af top of the cylinder indicates cylinder taper The cylinder nen sae ee should be measured for excessive taper and out of ioe eee cl al PRL OEEE SERRIAN astiti round Replace rings if the installed end gap exceeds Eoen ee the service limit Refer to page 3 3 for specifications rf HMLA dade NOTE Always check piston ring installed gap after re boring a cylinder or when installing new rings Re ci LLLL SELLER ttti Piston Pin Needle Bearing Inspection Clean needle bearing in solvent and dry with compressed air Inspect needle cage carefully for cracks or shiny spots which indicate wear Replace needle bearing if worn or cracked and always replace if piston damage has occurred 3 Visually inspect piston pin for damage discoloration or wear Run your fingernail along the length of the pin and replace it if any rough spots galling or wear is detected Measure piston pin Polaris Industries Inc 34a 10 96 ENGINE Disassembly Inspection Polaris Connecting Rod Small End Inspection 1 Clean small end of connecting rod and inspect inner bore with a magnifying glass Look for any surface irregularities including pitting wear or dents 2 Run your fingernail around the inside of the rod and check for rough spots galling or wear 3 Oil and install needle bearing and pin in connecting rod Rotate pin slowly and check for rough spots or any resistance to movement Slide pin bac
14. feed chamber cover with screw 6 Tighten screw securely 7 Install screen on pump body 8 Install oil pump on crankcase and torque bolts to 6 ft Ibs 828 kg m Counter Balancer Shaft Removal inspection 1 Remove the shim washer from the counter balancer shaft 2 Note the alignment dots on the balancer and crankshaft gears the marks must be aligned during reassembly 3 Remove the balancer shaft from the crankcase Polaris Industries Inc 3 71 7 96 ENGINE EH42PL EH50PL Engine Engine Disassembly Cont 4 Inspect the balancer drive gear and pump shaft drive gear 5 Replace the shaft if gear teeth are abnormally worn or damaged 6 Inspect the balancer shaft bearings NOTE Due to extremely close tolerances and minimal wear the balancer shaft ball bearings must be inspected visually and by feel Look for signs of discoloration scor ing or galling Turn the inner race of each bearing The bearings should turn smoothly and quietly The outer race of each bearing should fit tightly in the crankcase The in ner race should be firm with minimal side to side move ment and no detectable up and down movement Crankshaft Removal Inspection 1 Remove the shim washer from the crankshaft 2 Support the PTO side crankcase and crankshaft press the crankshaft out Be careful not to damage the crankcase mating surface or connecting rod 3 Useathickness gauge to measure the connecting rod big end
15. limiter troubleshooting chart Check and adjust ignition timing Repair or replace exhaust system Repair cylinder and piston as needed Clean repair or replace as required Repair or replace exhaust system Fill oil tank and bleed pump Check pump for proper operation pinched vent line Restricted oil delivery lines filter check valve Oil pump drive gear failure Install fan or check fan operation test cooling sys tem loose or broken impeller Clean carb and jet as per chart Repair as needed Use 87 octane minimum Adjust timing as per specifications Install recommended spark plug Repair cylinder Check air filter and air box Synchronize pump to carb refer to oil pump bleed ing and adjustment Lubricate or replace cable Inspect replace gasket Replace Polaris Industries Inc ENGINE 4 Stroke Troubleshooting Engine Turns Over But Fails to Start e No fuel e Dirt in fuel line or filter e Fuel will not pass through fuel valve e Fuel pump inoperative restricted e Tank vent plugged e Carb starter circuit e Engine flooded e Low compression high cylinder leakage e No spark Spark plug fouled Engine Does Not Turn Over e Dead battery e Starter motor does not turn e Engine seized rusted or mechanical failure Engine Runs But Will Not Idle e Restricted carburetor pilot system e Carburetor misadjusted e Choke not adjusted properly e Low compression e Crankcase
16. not properly timed to the crankshaft IMPORTANT CAMSHAFT TIMING NOTE In order to time the camshaft to the crankshaft the piston must be precisely located at Top Dead Center TDC This can be accomplished using one of two methods When the stator assembly is removed follow the pro cedure outlined in Method 1 This method uses the cam chain plated links to time the camshaft and the dot on the cam chain drive sprocket to establish TDC see Method 1 page 3 83 It is important to note that this method can only be used when the stator is removed and the cam chain drive sprocket is in view The plated links are not used to time the camshaft when the fly wheel is installed When the stator assembly is installed use Method 2 This method establishes accurate Top Dead Center TDC by aligning the single mark on the flywheel with the notch in the timing inspection hole see Method 2 page 3 85 The camshaft sprocket alignment pin faces upward and directly in line with the crankshaft to camshaft centerline 7 96 3 82 Polaris Industries Inc ENGINE EH42PL EH50PL Engine Assembly Cont Camshaft Installation Timing Method 1 Refer to Illustration Page 3 84 lf the stator assembly is removed NOTE Use this method only when the stator is removed and cam chain drive sprocket is in view 1 Rotate the crankshaft until the dot on the cam chain drive sprocket is aligned with the crankcase projection dot facing downward 2 Align
17. on both gears must be across from each other during reassembly See photo three at right Guide Washer O Ring Collar 19 Remove oil pump assembly D 20 Attach counterbalance puller onto counter balance and position as shown in the picture at right Reassembly Note The retainer bracket must be in position on the counterbalance assembly before the assembly is installed in the crankcase Polaris Industries Inc 3 29 7 96 ENGINE EC38PL Engine Disassembly Cont 21 Heat areas A and B with a small propane torch for approximately one to two minutes no closer than 1 2 5 cm from case areas WARNING Oil and gasoline are highly flammable and explosive under certain conditions Use extreme caution when using a propane torch in this environ ment 22 Once these areas are thoroughly heated add tension to the puller by turning the large nut Continue tensioning the puller until the counterbalance assembly is completely removed Reassembly Note For reassembly of counterba lancer heat areas A and B and press the balancer and bracket back into place 23 With counterbalance assembly removed follow instructions for crankshaft service on pages 3 13 3 15 24 The injection oil check valve is tested using the Mity Vac PN 2870975 With the Mity Vac in the pressure mode the check valve should release between 2 and 5 PSI 25 Remove the six bolts retaining the carb adapter and reed
18. pall 1 575 40 0 mm Squareness 075 1 9 mm 2 5 Valve Spring 7 96 24 Polaris Industries Inc ENGINE Service Data EH42PL EH50PL Engine Service Data Cylinder Piston Connecting Rod EH42PL EH50PL Cylinder Surface warpage limit mating with cylinder head 0020 05 mm 0020 05 mm Cylinder bore 3 4606 3 4614 87 900 87 920 mm 3 6216 3 6224 91 99 92 01 mm Taper limit 0020 050 mm 0020 050 mm Out of round limit 0020 050 mm 0020 050 mm 0006 0018 015 045 mm 0006 0018 015 045 mm Piston clearance td Limit 0024 060 mm 0024 060 mm Boring limit 020 5 mm 020 5 mm Piston Outer diameter 3 4596 3 4600 87 875 87 885 mm 3 6206 3 6210 91 96 91 97 mm 0098 25mm OS 3 4695 3 4699 88 125 88 135 mm 3 6304 3 6310 92 21 92 23 mm AF 0197 50 mm OS 3 4793 3 4797 88 375 88 385 mm 3 6403 3 6407 92 46 92 47 mm Standard inner diameter of piston pin bore 9055 9057 23 0 23 006 mm 9055 9057 23 0 23 006 mm Piston Pin 9053 9055 22 994 23 0 mm 9053 9055 22 994 23 0 mm 0002 0003 004 008 mm 0002 0003 004 008 mm Piston pin must be a push by hand fit at 68 F 20 C Top ang MN er a 7 Second Std 0079 0138 20 36 mm 0079 0138 20 36 mm ring Limit 039 1 0 mm 039 1 0 mm Oil ring Std 0079 0276 20 70 mm 0079 0276
19. recoil can be assembled with the engine in the frame Stator 1 Apply alight film of grease to the crankshaft seal Apply molybdenum disulfide grease or assembly lubricant to the crankshaft bushing 2 Install anew O Ring in the oil passage recess in the crankcase 3 Apply 3 Bond 1215 Loctite 515 or 518 or an equivalent sealer to the stator plate outer surface and install a new O Ring 4 Install the stator plate being careful not to damage the seal Align timing reference marks on the plate and crankcase Be sure the plate is fully seated Polaris Industries Inc 3 87 7 96 ENGINE EH42PL EH50PL Engine Assembly Cont 4 Torque bolts evenly to specification 5 Seal stator wire grommet with 3 Bond 1215 or equivalent sealer Flywheel 1 Install flywheel washer and nut Torque flywheel to specification Starter Drive 1 Be sure the washer is positioned on the back of the drive gear 2 Apply grease to the drive bushing in the crankcase and all moving surfaces of the starter drive mechanism Install the starter drive 3 Install recoil housing gasket and recoil housing 5 98 3 88 Polaris Industries Inc ENGINE EH42PL EHS50PL Engine Assembly Cont Rocker Shaft Rocker Arm Assembly Installation Assemble rocker arms rocker shaft and shaft supports Install and tighten rocker arm shaft locating bott Apply molybdenum disulfide grease to the cam lobes and cam follower surfaces Rot
20. screw A for a few seconds then tighten Install the air box and filter element NOTE Ifthe crankcase or oil pump have been replaced check the oil pump end play as outlined on page 3 20 2 Make sure the vent line from the carburetor is routed to the upper part of the frame B Check the vent line and be sure it is not pinched or kinked 3 Install PVT system as outlined in PVT section Be Sure to inspect clutch offset alignment and belt deflection and adjust if necessary 4 Torque drive clutch retaining bolt to 40 ft Ibs 5 5 kg m Torque driven clutch retaining bolt to 17 ft Ibs 2 85 kg m Polaris Industries Inc 3 19 7 96 ENGINE EC25PF EC28PF Engine Assembly Oil Pump End Play Adjustment The oil pump is a positive displacement type pump Whenever the oil pump oil pump bushing or crankcase are replaced the end play clearance must be checked Target clearance is 008 024 2 6mm between the oil pump boss and the bushing in the crankcase Symptoms of excessive gear end play include noticeable engine noise at idle pump lever arm binds in the 1 2 open position will release when engine is rotated NOTE Some 250 300 cc ATV engine oil pumps were produced with a plastic oil pump drive gear PN 3084825 The plastic drive gear is no longer available and subs to a metal drive gear PN 3083429 If you are replacing a plastic drive gear with a metal one you must also order and install thrust washer PN 3083428
21. side clearance 7 96 3 72 Polaris Industries Inc ENGINE EH42PL EH5OPL Engine Engine Disassembly Cont 4 Place the crankshaft in a truing stand or V blocks and measure the runout on both ends with a dial indicator 5 Measure the connecting rod big end radial clearance 6 Inspect the crankshaft main bearing journals for scoring and abnormal wear Crankcase Bearing Inspection 1 Remove the seal from the PTO side crankcase 2 Inspect the crankshaft main bearings balancer shaft bearings and pump shaft bearing NOTE Due to extremely close tolerances and minimal wear the bearings must be inspected visually and by feel Look for signs of discoloration scoring or galling Turn the inner race of each bearing The bearings should turn smoothly and quietly The outer race of each bearing should fit tightly in the crankcase The in ner race should be firm with minimal side to side move ment and no detectable up and down movement 3 Support the crankcase and drive or press the main bearings out of each crankcase 4 Toremove balancer shaft bearings and pump shaft bearing use a blind hole bearing puller NOTE Bearings are stressed during the removal process and should not be re used Pump Shaft Oil Seal Water Pump Mechani cal Seal Removal Replace the pump shaft seal and water pump mechani cal seal whenever the crankcase is disassembled 1 Remove the pump shaft bearing from the Magneto right han
22. the pump shaft seal and install the magneto end crankshaft installation tool follow instructions provided with tool kit PN 2871283 Draw the crankcase halves together by tightening the nut on the tool and tapping lightly in the pump shaft area with a soft faced hammer to maintain alignment Continually check alignment of the cases during installation closing the gap equally until the surfaces are tightly seated 3 Remove the tool 4 Install the crankcase flange bolts and tighten in 3 steps in a criss cross pattern to specified torque Polaris Industries Inc 3 77 5 98 ENGINE EH42PL EH50PL Engine Water Pump Mechanical Seal Installation 1 Clean the seal cavity to remove all traces of old sealer Place a new mechanical seal in the seal drive collar and install on the pump shaft Screw the guide onto the end of the pump shaft Install the washer and nut and tighten to draw seal into place until fully seated oY 2 ae S Remove the guide adaptor using the additional nut as a jam nut if necessary Water Pump Mechanical Seal Removal Engine Installed Water pump mechanical seal removal tool 2872105 Replacement T handle for 2872105 2872106 This tool allows a technician to replace the mechanical water pump seal on EH42PL amp EHS50PL engines without removing the engine and splitting the cases Improper or careless use of this tool or procedure can result in a bent water pump shaft Pump shaft replacement requires engine
23. the shaft and the high spot is found with the rod in this position see photo at right the crankshaft wheels will have to be spread apart Place a large chisel between the wheels and force the chisel downward This will open the wheels and bring the end of the shaft down B Arrows show the direction of force to be applied 4 Ifthe indicators are moving in opposite directions while turning the shaft the shaft is twisted To correct this remove the shaft from the fixture and strike the high spot found on the left side indicator NOTE Squeezing the crank wheels is always done opposite the high spot Spreading the crank wheels is always done at the high spot Twisting the crank wheel by striking it is always done at a right angle to the lower rod pin and at the high spot Polaris Industries Inc 3 13 7 96 ENGINE EC25PF EC28PF Engines Assembly Before reassembling the crankcase the following steps should be performed to determine the amount of crank shaft end play Excessive end play will cause the engine to be noisy at idle and slow speeds Too little end play will side load the main bearings which may cause premature bearing failure Measure Crankshaft Width Bearings Installed 1 Measure distance from outer edge of PTO end bearing race to outer edge of mag side bearing race Record measurement If bearings and spacers are already installed measure distance as shown in photo at right then proceed to Step 5 O
24. the single plated link on the cam chain with the dotted tooth of the cam chain drive sprocket Use a wire to pull the chain up through the cylinder and cylinder head and secure it to hold the chain in place 3 Apply Polaris Low Temp Grease PN 2870577 or moly grease to the camshaft main journals and cam lobes Lubricate automatic compression release mechanism with clean engine oil To install the compression release mechanism refer to page 3 48 4 Install the camshaft with the lobes facing downward and the sprocket alignment pin facing upward 5 Disconnectthe wire from the cam chain and install the cam sprocket with the two dots facing outward 6 Loop the cam chain over the cam sprocket aligning the two plated links on the chain with the two dots on the sprocket 7 Install the sprocket on the camshaft Apply Loctite 242 to the cam sprocket boits and torque to specifications 8 Apply Loctite 515 or 518 Gasket Eliminator to the camshaft end cap and install using a new O ring 9 Check all cam timing marks to verify proper cam timing and install the cam chain tensioner See Cam Chain Tensioner Installation page 3 87 NOTE The plated links will not align after engine is rotated Polaris Industries Inc 3 83 7 96 ENGINE EH42PL EH50PL Engine Assembly Method 1 Camshaft Timing with Stator Removed Two Plated Links Two Dots on sprocket i f ci Ap Single Plated Link and Dot on Cam Eas Ch
25. three steps to 17 ft Ibs 2 3 kg m following pattern shown on page 3 2 NOTE Before proceeding check piston to cylinder clearance and ring end gap page 3 34 and cylinder honing procedures page 3 33 17 Install piston rings beveled side up onto piston Piston Ring Cutaway Keystone rings are beveled to the inside This bevel must be toward the top of the piston letter and or number marks near end gap of ring face upward Keystone Ring 7196 3 16 Polaris Industries Inc Assembly Cont 18 Position C clip onto driver PN 2870773 with open end down as shown Slide barrel over driver Toward Flywheel C clip retainers open end should be traight up or Straight down 19 Install guide pin at the driver into the piston pin and position the barrel up against the piston While holding the barrel against the piston push the driver in until you hear the clip engage into the piston groove Visually inspect the C clip to be sure it is fully seated 20 Rotate driver to complete engagement of clip 21 Reinstall piston onto rod with F mark or toward the magneto side of the engine Support with support block 22 Lubricate piston pin and pin bearing 23 Reinstall piston pin patent eraerseesey HEITIT fete uno api eal iP Wr pR uR pih Hiu pitt Aistseiesi tt eho su ayenieeedd ERAS itty Asti Sata sas yetin PAPAI hia tie tant e i 1 ul ait Peal wen ui J j
26. valve assembly using an 8 mm socket NOTE The reed stuffer is standard on the 400L models 2 Reed Stuffer 7 96 3 30 Polaris Industries Inc ENGINE EC38PL Engine Disassembly Cont Reed Valve Assembly 26 Measure reed stop height in the area A indicated Recommended stop height is 350 9 mm 27 Measure the air gap of each reed valve petal as shown in the photo at right The air gap should not exceed 015 4 mm NOTE An early sign of reed valve failure may be hard starting 28 Check each reed valve petal for white stress marks or missing material Replace if necessary Water Pump Impeller Clearance Whenever the counterbalance assembly is removed it will be necessary to verify impeller clearance Fol lowing is a recommended procedure for measuring water pump impeller clearance 29 Apply asmall amount of putty or clay to the top of one impeller blade B 30 Reinstall case gasket and bolt case together at areas C and D as indicated on the photo at right 31 Carefully remove case cover Polaris Industries Inc 3 31 7 96 ENGINE EC38PL Engine Disassembly Cont 5 Remove water pump impeller and check clearance measurement Acceptable clearance measured with a dial caliper is between 020 040 05 1 cm CAUTION lf the clearance is less than 020 05 cm the impeller may grind against the case If the clearance is more than 040 1 cm the water pump may cavit
27. 3 61 Polaris Industries Inc ENGINE EH42PL EH50PL Engine Engine Disassembly Cont Using a piston ring pliers Carefully expand ring and lift it off the piston CAUTION Do not expand the ring more than the amount necessary to remove it from the piston or the ring may break By hand Placing both thumbs as shown spread the ring open and push up on the opposite side Do not scratch the ring lands 4 Repeat procedure for second ring The oil control ring is a three piece design consisting of a top and bottom steel rail and a center expander section The top rail has a locating tab on the end which fits into a notch in the upper oil ring land of the piston 5 Remove the top rail first followed by the bottom rail 6 Remove the expander Cylinder Inspection Remove all gasket material from the cylinder sealing surfaces n S pe ct t h e to p of t h e cyl i n d e r fo r W a rp ag e u Si n g a i m R paes La a jini straight edge and feeler gauge ae HHIH h dhan Matte tie APANAR Hi AAAH PAANI 44 PEETI w ia i eet ibenta Inspect cylinder for taper and out of round with a elescoping gauge or a dial bore gauge Measure in wo different directions front to back and side to side on three different levels 1 2 down from top in the middle and 1 2 up from bottom 7 96 Polaris Industries Inc ENGINE EH42PL EHS50PL Engine Engine Disassembly Cont 2 Record measuremen
28. 40 Polaris Industries Inc ENGINE EH42PL EHS50PL Engine Removal Cont 5 Remove the following Starter motor Note ground cable location Mark positive cable mounting angle and remove cable e Oil tank bolts and oil tank securing it out of the way e Oil filter Cover oil filter area with a shop towel 6 Loosen oil line hose clamps and remove oil lines NOTE The uppermost line is the oil feed from the bottom of the tank Cover both oil lines to prevent dirt from entering the line 7 Remove coolant tank Torx screws and remove tank Secure out of the way 8 Loosen clamp and remove coolant line from thermostat housing Drain the line into a suitable container Plug end of thermostat housing to minimize spillage NOTE Mark the center of the engine mount studs in the frame for reference upon installation 9 Remove nut ground cable and washer from the upper right engine mount and mark the location of the center of the mount stud 10 Remove the two upper engine mount plate bolts and remove the plate and ground cable 11 Remove nut and washer from lower left engine mount and mark location of stud Some engines have the front motor mount located in front of the engine Polaris Industries Inc 3 41 10 96 ENGINE EH42PL EH50PL Engine Removal Cont 17 Loosen nut on slotted rear engine mount plate and back it out to the end of the stud Final Coolant Draining Engine Removal 1 Move top of engi
29. CHAPTER 3 ENGINE Torque SpeciiCallONS sacencunitestiGvasestseugiet ee 3 1 Torgue Pates iccvonscewyeeteceess Sines 3 2 Specifications 1996 to Current 4 3 3 Piston Identification Installation 3 3 EH42PL 01 EH50PL 01 Service Data 3 4 3 5 Cooling System Pressure Test 08 3 6 Cooling System Specifications 0 3 7 Engine Removal Installation 0 3 8 3 11 EC25PF EC28PF Engine Disassembly 3 12 EC25PF EC28PF Crankshaft Alignment 3 13 EC25PF EC28PF Engine Assembly Installation 3 14 3 19 EC25PF EC28PF Oil Pump End Play Adjustment 3 20 EC25PF EC28PF Oil Check Valve Testing 3 21 EC25PF Recoil Disassembly Assembly 3 22 3 24 EC38PL Engine Disassembly 0 3 25 3 32 Cylinder HONING itor teemineeatiedae ete etees 3 33 3 34 Polaris Engine Disassembly Inspection 3 34a 3 34b EH42PL EH50PL Engine Exploded View 3 35 EH42PL EH50PL Engine Lubrication 3 36 EH42PL EH50PL Oil Flow Chart 3 37 EH42PL EH50PL Engine Removal 3 38 3 42 EH42PL EH50PL Engine Installation 3 43 EH42PL EH50PL Engine Disassembly Inspection 3 43 3 73 EH42PL EH50PL Engine Assembly 3 74 3 89 Water Pump Mech Seal Removal Engine Installed 3 77a 3 77b Sealed Recoil Disassembly Insp
30. If the contact area is less than 75 of the cir cumference of the seat rotate the pilot 180 and make another light cut e Ifthe cutter now contacts the uncut portion of the seat check the pilot Look for burrs nicks or runout If the pilot is bent it must be replaced e Ifthe contact area of the cutter is in the same place the valve guide is distorted from im proper installation and must be replaced Be Sure the cylinder head is at the proper temper ature and replace the guide e If the contact area of the initial cut is greater than 75 continue to cut the seat until all pits are removed and a new Seat Surface is evi dent NOTE Remove only the amount of material necessary to repair the seat surface 5 To check the contact area of the seat on the valve face apply a thin coating of Prussian Blue paste to the valve seat 6 Insert valve into guide and tap valve lightly into place a few times Polaris Industries Inc 3 57 7 96 ENGINE EH42PL EH50PL Engine Engine Disassembly Cont te 10 Tl 12 Remove valve and check where the Prussian Blue indicates seat contact on the valve face The valve seat should contact the middle of the valve face and must be the proper width Ifthe indicated seat contact is too high on the valve face use the 30 or 31 cutter to lower the valve seat If too low use the 60 or 75 cutter to raise the seat When contact area is centered on the valve f
31. K ee O ji i Bebssre rset ecdd dad SAR ds atta AA et ssopmne dda iam g Ratti eH N Haliti reer D bbb beat CRN aR g Sere atts EN eS t tititi rta H fi e ann RETIER on H piiriin Hi 4 p ENIRON i i ETETEA EEIN tft Hi fratan tit HHA AA AAAA AAAAAAAAAAAAAAAAA AAAA LAARA AA AAAA AAAA AAAA AAAA ni TLMT Pinsaia AAAH iA PETN HAE ASAAN TTR TR Tet ERRENTEN 3 Apply clean engine oil liberally tothe cylinderboreand p 7 E tapered area of the sleeve Install the cylinder with a Oe ee lll 7 i n i TOLER RS PRR Minds 4 eres Wert sepbesseebs tas Ee ee ee vad So CSTE aa f i prep eet slight rocking motion until the rings are captive in the Sn f sleeve and remove the ring compressor oe ge ee BI cra MITTERE hasis Rie SMT yi Thal ua Tan sede ie te no Perit hni Cd i R rT HAAA a iE AEA i taa Aas de dd eapi HN Tabb cue H EH ada HADA OP gt Wee te Hi DHPARIRRA en Cate ite nH POTERIE ERETTI n Tis renddaa ge h aad Huj RHH giki SENSE esr MaSeSEMireerstretal ery h LAE hiha HAIAIAIAN PITOA AIREAREN ARTETA Tap tae tees COLET STEETET TORRE Rertesrr eyes ttte nt Hedi iebeshas Risrarstet tbealtasiesegee HAIER RH AA i Ara HRY pipihi CO HHH Athy Toasdansn fete pR Puji hy ARRE RE E A tee eR AEH ali i ia R reer ee eee AML i A IAA E EAA ISI tee Hittin Star Stn non TEESE SITE a PPO SITET SSSI SNCS TERN in ah
32. NE Engine Removal Engine Removal Preparation Cont 23 Move top of engine to left until coolant supply hose clamp clears frame at water pump fitting 24 Lift and twist engine clockwise until lower left engine mount stud is clear of frame mount and the lower right coolant hose clamp clears frame tube 25 Support engine in this position with a suitable support such as a board or a 2x4 26 Place a drain pan beneath area to catch coolant 27 Clamp coolant inlet hose leading from radiator to pump to reduce coolant spillage 28 Remove hose from water pump inlet and place in container Release clamp from hose and allow hose to drain completely 29 Lift back of engine while rotating front of engine clockwise and remove engine from left side of frame 7 96 3 10 tf H beri H CONONNONONOONOONOENOENOUNOUOUOOUNONOEPOONOENOUOENOUOOUOOUOON idl Polaris Industries Inc ENGINE Engine Installation Engine Installation Notes 2 Stroke Bleed Cooling System 1 Fill coolant reservoir tank to full mark 2 Loosen bleed screw at top of cylinder head until all air is purged from coolant system Tighten bleed screw 3 Install radiator cap and squeeze coolant lines to force air out of system NOTE Radiator must be full or coolant will not circulate and reservoir will not refill radiator 4 Remove cap and add coolant if necessary 5 Afterreassembly is complete start engine and observe coolant level in the radiator Al
33. PL Engine Engine Disassembly Cont 6 Measure valve guide inside diameter at the top middle and end of the guide using a small hole gauge and a micrometer Measure in two directions front to back and side to side 7 Subtract valve stem measurement to obtain stem to guide clearance NOTE Be sure to measure each guide and valve combination individually 8 Replace valve and or guide if clearance is excessive NOTE If valve guides are replaced valve seats must be reconditioned Combustion Chamber Clean all accumulated carbon deposits from combustion chamber and valve seat area with a soft wire brush Valve Seat Inspection Inspect valve seat in cylinder head for pitting burnt spots roughness and uneven surface If any of the above conditions exist the valve seat must be reconditioned See Valve Seat Reconditioning page 3 56 f the valve seat is cracked the cylinder head must be replaced Cylinder Head Reconditioning NOTE Servicing the valve guides and valve seats requires special tools and a thorough knowledge of recondi tioning techniques Follow the instructions provided in the cylinder head service tool kit CAUTION Wear eye protection when performing cylinder head service Valve guide replacement will require heating of the cylinder head Wear gloves to prevent burns Valve Guide Removal Installation 1 Remove all carbon deposits from the combustion chamber valve seat and valve guide area before attemp
34. Remove spring retainer and spring NOTE The valve springs should be positioned with the tightly wound coils against the cylinder head 3 Push valve out keeping it in order for reassembly in the same guide 7 96 3 5 Polaris Industries Inc ENGINE EH42PL EH50PL Engine Engine Disassembly Cont 4 Measure free length of spring with a Vernier caliper Check spring for squareness Replace spring if either measurement is out of specification Coil Fatique Squareness 5 Remove valve seals CAUTION Replace seals whenever the cylinder head is disassembled Hardened cracked or worn valve seals will cause excessive oil consumption and carbon buildup Polaris Industries Inc 3 53 7 96 ENGINE EH42PL EH50PL Engine Engine Disassembly Cont Valve Inspection 1 Remove all carbon from valve with a soft wire wheel 2 Check valve face for runout pitting and burnt spots To check for bent valve stems mount valve in a drill or use V blocks and a dial indicator 3 Check end of valve stem for flaring pitting wear or damage 4 Inspect split keeper groove for wear or flaring of the keeper seat area NOTE The Stellite valves cannot be re faced or end ground They must be replaced if worn bent or damaged 5 Measure diameter of valve stem with a micrometer in three places and in two different directions six measurements total 7 96 3 54 Polaris Industries Inc ENGINE EH42PL EH50
35. ace measure seat width e If the seat is too wide or uneven use both top and bottom cutters to narrow the seat Ifthe seat is too narrow widen using the 46 cutter and re check contact point on the valve face and seat width after each cut Clean all filings from the area with hot soapy water rinse and dry with compressed air Lubricate the valve guides with clean engine oil and apply oil or water based lapping compound to the face of the valve Insert the valve into its respective guide and lap using a lapping tool or a section of fuel line connected to the valve stem Rotate the valve rapidly back and forth until the cut sounds smooth Lift the valve slightly off of the seat rotate 1 4 turn and repeat the lapping process Do this four to five times until the valve is fully seated and repeat process for the other three valves Remove oil passage blind plug and thoroughly clean cylinder head and valves 7 96 3 58 A Seating Surface Polaris Industries Inc ENGINE EH42PL EH50PL Engine Engine Disassembly Cont 13 After cylinder head and oil passage are clean apply 3 Bond 1215 or equivalent sealer to the threads of the blind plug and install torquing to 8 ft Ibs 1 1 kg m CAUTION Do not allow sealer to enter oil passage 14 Spray electrical contact cleaner into oil passage and dry using compressed air Cylinder Head Assembly CAUTION Wear eye protection during assembly NOTE Assemble
36. age to the one way valve When the engine is off the one way valve closes to prevent oil in the tank from draining into the crankcase The oil is pumped through a delivery pipe to the oil filter If the oil filter is obstructed a bypass valve contained in the filter allows oil to bypass the filter element At this point the oil is diverted in two directions Oil is supplied to the camshaft through the left front cylinder stud and an oil passage in the head Oil enters the camshaft through the PTO L journal The camshaft journals cam lobes and rocker arms are lubricated through holes in the camshaft The oil lubricates the cam chain and sprocket and drains to the sump The other oil path from the filter leads through a delivery pipe to the crankcase main oil gallery which leads to the stator plate oil passage Here it passes through the slotted friction bearing into the crankshaft An oil seal on the stator plate prevents oil from entering the stator flywheel area Oil travels through the crankshaft to the crank pin lubricating the connecting rod large end bearing directly Oil also passes through an oil jet drilled ori fice in the end of the crank pin to the PTO end main bearings and counterbalancer gears Residual oil from the lubrication of the crankshaft and connecting rod indirectly lubricates the cylinder wall piston rings connecting rod small end bearing piston pin oil water pump drive gears cam chain and drive sprocket and Mag
37. ain Drive Crankcase Projection Sprocket NOTE Plated links will not align after engine is rotated 10 96 3 84 Polaris Industries Inc Assembly Cont ENGINE EH42PL EHS50PL Engine Camshaft Installation Timing Method 2 Refer to Illustration Page 3 86 I Polaris Industries Inc Apply Polaris Low Temp Grease PN 2870577 or molybdenum disulfide grease to the camshaft main journals and cam lobes Lubricate automatic compression release mechanism with clean engine oil To install the compression release mechanism refer to page 3 48 Install the camshaft with the lobes facing downward and the sprocket alignment pin facing upward Disconnect the wire from the cam chain and rotate the engine to align the single TDC timing mark Top Dead Center on the flywheel with the notch in the timing inspection window Be sure to use the single TDC mark when instailing the cam Do not use the advance marks See III on next page Loop the cam chain on the cam sprocket with the dots on the sprocket facing outward and the alignment pin notch facing directly upward Before positioning the sprocket on the camshaft check the position of the cam sprocket alignment pin When the cam is positioned properly the cam sprocket alignment pin is directly in line with the crankshaft camshaft centerline Install the sprocket on the camshaft Apply Loctite 242 to the cam sprocket bolts and torque to specifications Apply Loctite 515 or
38. amage check compression PVT not operating properly Plugged exhaust Engine has low power Piston failure Lack of lubrication Scoring Melted piston top Engine overheating Lean air fuel ratio Air leak in crankcase Low octane fuel Incorrect ignition timing Incorrect spark plug Piston fatigue from scoring Excessive piston to cylinder clear ance Oil pump misadjusted Skirt breakage Excessive smoke and carbon buildup Oil pump cable not allowing pump to return to idle position Engine coolant found in counter balance assem bly Liquid cooled moa els Water pump gasket Water pump seal 7 96 3 94 ETC limiting speed 1989 and newer Repair vent system Clean or replace as needed Turn off fuel and drain crankcase a Inspect carb venting system for obstructions b Inspect carb needle and seat a Inspect head gasket b Inspect piston and cylinder repair as required Repair ignition system refer to ignition trouble shooting Charge or replace battery refer to battery testing Repair starter refer to starter testing Repair engine as required Clean or replace pilot jet Adjust as per specification Adjust choke as per specification Repair engine as required Repair crankcase as required Replace cable Clean or repair air intake Jet as per jetting chart Repair ETC refer to ETC troubleshooting Repair reverse speed limiter refer to reverse speed
39. and rocker arms and cylinder head 1 Remove cam chain guide at front of cylinder 2 Loosen all four oil pipe banjo bolts and then remove the bolts and eight sealing washers Remove the pipes 3 Loosen hose clamps on coolant inlet hose and remove hose 7 96 3 60 Polaris Industries Inc ENGINE EH42PL EH50PL Engine Cont isassembly D Remove the two 6 mm cyl ine Eng inder base bolts 4 ud a iiep ide the ins cross pattern der base bolts Loosen each of the four cylin 5 in a criss Ime ket 1 4 turn at a ti ioose jac water Remove the bolts unt 6 ab A a prar _ tab E E J Oo D T a Q w O o Ss s 5 e c oO D w 8 _ Oo a o Dn O 5 2 5 Ev N t from the inder forward and backward and Rock cyl crankcase 8 iston and connecting rod supporting p th piston support block PN 2870390 ins from crankcase IS ton wi Support p Remove dowel p 9 Piston Removal 1 Note piston directional arrow pointing toward the Magneto right side of the engine ton pin out of piston IS ip and push p If necessary heat the crown of the p propane torch CAUTION ircl iston ci Remove p 2 lightly with a Do not apply heat to the ing may lose rad tons IS tension la ings Ther piston r ion ring Remove top compress 3 7 96
40. ap nas 5 6 ft lbs 69 828 kg M 6 9 8 28 N m Cam Chain Tensioner Plug 11mm 14 19 ft Ibs 1 93 2 62 kg m 19 3 26 2 N m Rocker Arm Shaft Support 8mm 8 9 ft Ibs 1 10 1 24 kg m 11 0 12 4 N m Rocker Arm Adjuster Nut 6mm 6 7 ft DSi 3 aieeeeaes 828 966 kg M 8 28 9 66 N m Water Pump Impeller Nut 6mm 5 6 5 ft Ibs 69 897 kg m 6 9 8 97 N m Water Pump Cover 6mm 5 6 5 TADS presses 69 897 kg M 6 9 8 97 N m Carburetor Flange 8mm 12 14 ft Ibs 1 66 1 93 kg m 16 6 19 3 N m Oil Pump Mount Bolts 6mm 5 6 5 ft lbs 69 897 kg M 6 9 8 97 N m Oil Pump Case Screws 5MM 60 2 ft Ibs e054 aes 210 Kg M oaan 27 6 N m Union Breather io a eee 6 5 11 ft lbs 897 1 52 kg m 8 97 15 2 N m Union Oil Hose EPT sess 6 5 11 ft Ibs 897 1 52 kg m 8 97 15 2 N m Union Oil Filter 20mm 36 43 ft Ibs 4 97 5 93 kg m 49 7 59 3 N m Oil Pressure Blind Plug 1 8 PT 6 5 11 ft Ibs 897 1 52 kg m 8 97 15 2 N m Oil Delivery Pipe 12mm 18 25 ft Ibs 2 48 3 45 kg M 24 8 34 5 N m Oil Drain Bolt Crankcase 14mm 14 17 ft Ibs 1 93 2 35 kg m 19 3 23 5 N m Plug One Way Va
41. ary Transmission 1 Readjust transmission shift linkage as outlined in Transmission Chapter Exhaust a 2 Seal all connections with high temp silicone seal Check to be sure all springs are in good condition Engine Disassembly Cam Chain Tensioner Rocker Arm Camshaft Removal l 2 3 Remove fuel tank and spark plug high tension lead If camshaft is to be removed drain engine coolant See cooling system draining refilling Remove bolt securing rocker cover and remove cover and gasket Remove ignition timing inspection plug from recoil housing Polaris Industries Inc 3 43 7 96 ENGINE EH42PL EH50PL Engine Engine Disassembly Cont To position crankshaft at Top Dead Center TDC on compression stroke 12 Rotate engine slowly in the direction of rotation watching intake valves open and start to close 13 Continue to rotate engine slowly watching camshaft sprocket marks and the mark in the timing inspection hole 14 Align single TDC mark on flywheel with projection in inspection hole and the cam sprocket pin facing upward aligned with the camshaft to crankshaft center line NOTE The cam lobes should be pointing down and all valves should have clearance at this point 15 Remove cam chain tensioner plug sealing washer and spring CAUTION The plug is under spring tension Maintain inward pressure while removing 16 Remove the two 6x25 mm cam chain tensioner flange bolts 17 Tap light
42. ate 6 The photo at right illustrates checking clearance measurement with a feeler gauge This method may also be used to check thickness by removing half of the putty from the impeller blade Spacer shim part numbers PN 3084188 0 1 mm 004 PN 3084189 0 2 mm 008 The illustration depicts correct positioning of the seals The water 4G NN T al Counterbalancer ga seal is identified by counting the FS number of sealing lips It is a triple Wage p lip seal and has a protruding edge we Lip Spring Toward that faces away from the spring e Counterbalancer The oil seal is a double lip variety Pa The lip on the spring end angles Po back toward the spring The spring wa end of the seals open side must face the oil or coolant as shown in Oil Seal Water Seal i Closed Side 3084184 3084185 the illustration Toward Each NS Lip Spring Toward Impeller To assemble the pump casing Other press the bearing into the casing until flush with the casting Note Do not press the bearing in until it seats against the shoulder or the Press Oil Seal oil hole will be covered by the bear Past Weep Hole ing outer race Next press the oil seal into the seal bore until the weep hole is visible Now press the water seal in until flush with the out er edge of the seal bore Oil Hole Weep Hole Press Water Seal Flush 5 98 3 32 Polaris Industries Inc ENGINE Cylinder Hone Selection H
43. ate the engine until the cam lobes are pointing downward Be sure the dowel pins are in place and install the rocker shaft assembly Apply a light film of engine oil to the threads of the bolts and tighten evenly Ok Fee a 7 Adjust valves according to the valve adjustment procedure found in Chapter 2 Maintenance 8 Apply clean engine oil liberally to the valve springs cam chain rocker arms and camshaft 9 Place a new rocker cover gasket on the cylinder head and install the cover and bolts Thermostat Installation Install the thermostat with one of the air bleed holes positioned next to the upper thermostat cover bolt hole as shown Oil Pipes Install the oil pipes with new sealing washers Tighten all bolts evenly to specified torque Polaris Industries Inc 3 89 7 96 ENGINE Sealed Recoil Recoil Disassembly Inspection CAUTION The recoil is under spring tension A face shield and eye protection is required during this proce dure Replace any parts found to be worn or damaged 1 Remove bolts and recoil housing 2 Pull recoil rope so it is fully extended and tie a loose knot at the rope guide bushing 3 Check handle for cracks or damage which may allow water or dirt to enter the recoil housing through the rope NOTE The handle must also seal tightly on the recoil housing to prevent water from entering 4 Pull knot out of of recoil reel Untie knot remove rope from reel 10 96 3 90 Polar
44. ate the housing three more turns and install the pawl return spring with the large end of the spring going into rope housing reinstall retainer plate lock washer and bolt 5 Check recoil and ratchet operation 6 When reinstalling assembly onto engine use Loctite 515 Gasket Eliminator between the flywheel housing and crankcase 10 96 3 24 Polaris Industries Inc Disassembly NOTE To reassemble engine reverse the following procedure paying attention to reassembly notes as in dicated 1 Refer to page 3 8 and follow engine removal instructions This engine will also require removal of coolant lines and the sending unit wire mounted at the rear of the cylinder head 2 Remove the six bolts retaining the starter assembly and flywheel cover Reassembly Note During reassembly apply Loctite 518 to mating surfaces of starter cover assembly and crankcase assembly 3 Remove starter pulley and flywheel nut 4 For starter removal remove bolts retaining starter bracket on PTO side and two bolts A on mag side NOTE f starter inspection is necessary make sure during reassembly that the gear shaft washer B is in place between the gear shaft assembly and starter mo tor for reassembly Starter damage will occur if this washer is not correctly positioned For detailed service and repair of electric starters and starter drives refer to Chapter 8 of this Service Manual ENGINE EC38PL Engine Polaris Industr
45. ating the outer race A If the bearing s feel rough they must be replaced Check the crankshaft runout by sliding a bearing onto the PTO end B and clamping the shaft into the special holding fixture PN 2870710 The shaft should be straightened to 002 05 mm or less 10 96 3 12 Polaris Industries Inc ENGINE EC25PF EC28PF Engines Crankshaft Alignment When the crankshaft runout exceeds 005 15 mm it must be straightened or replaced To straighten a crank shaft the crank wheel s must be relocated on the lower rod pin The four basic movements which may be required to realign the crankshaft are listed below 1 If the dial indicators are moving in the same direction and approximately the same amount while the shaft is rotated the crankshaft has twisted on the lower rod pin To correct this remove the shaft from the fixture and strike the crank wheel on the high spot A This will rotate the wheel on the lower rod pin 2 If the right side indicator is moving more than the left indicator while turning the shaft and the high spot is found with the rod in this position see photo at right the crankshaft wheels will have to be Squeezed together Remove the shaft from the fixture Locate the high spot and squeeze directly opposite from it using a large channel lock pliers or a vise Arrows show direction of force to be applied 3 If the right side indicator is moving more than the left indicator while turning
46. breather restricted Engine Idles But Will Not Rev Up e Spark plug fouled weak spark e Broken throttle cable e Obstruction in air intake e Air box removed reinstall all intake components Incorrect or restricted carburetor jetting e ETC switch limiting speed e Reverse speed limiter limiting speed e Carburetor vacuum slide sticking diaphragm damaged e Incorrect ignition timing e Restricted exhaust system Engine Has Low Power e Spark plug fouled e Cylinder piston ring or valve wear or damage check compression e PVT not operating properly e Restricted exhaust muffler e Carburetor vacuum slide sticking diaphragm damaged e Dirty carburetor Piston Failure Scoring e Lack of lubrication e Dirt entering engine through cracks in air filter or ducts e Engine oil dirty or contaminated Polaris Industries Inc 3 95 7 96 ENGINE 4 Stroke Troubleshooting Excessive Smoke and Carbon Buildup Excessive piston to cylinder clearance Wet sumping Worn rings piston or cylinder Worn valve guides or seals Restricted breather Air filter dirty or contaminated Low Compression Decompressor stuck Cylinder head gasket leak No valve clearance or incorrectly adjusted Cylinder or piston worn Piston rings worn leaking broken or sticking Bent valve or stuck valve Valve spring broken or weak Valve not seating properly bent or carbon accumulated on sealing surface Rocker arm sticking Overheating Low coolant l
47. d actuator ball will be held in the out position It is important to note that spring pressure is very light Atini 7 96 Polaris Industries Inc ENGINE EH42PL EH50PL Engine Engine Disassembly Cont Camshaft Inspection 1 Visually inspect each cam lobe for wear chafing or damage 2 Thoroughly clean the cam shaft making sure the oil feed holes are not obstructed 3 Measure height of each cam lobe using a micrometer 4 Measure camshaft journal OD 5 Measure ID of camshaft journal bore 6 Calculate oil clearance by subtracting journal OD from journal bore ID Polaris Industries Inc 3 49 10 96 ENGINE EH42PL EH50PL Engine Engine Disassembly Cont Replace camshaft if damaged or if any part is worn past the service limit Replace cylinder head if camshaft journal bore is damaged or worn excessively 7 Inspect camshaft end cap thrust face for wear Replace if worn or damaged Cylinder Head Removal See appropriate chap ter to remove the follow ing fuel tank spark plug high tension lead exhaust pipe carbure tor and top engine mount plate Drain coolant Remove cam chain tensioner cam shaft and rocker as sembly 7 96 3 90 Polaris Industries Inc ENGINE EH42PL EH50PL Engine Engine Disassembly Cont 1 Remove the two 6x28 mm flange bolts from cylinder head 2 Loosen each of the four 11x191 mm cylinder head bolts evenly 1 8 turn each time in a cris
48. d side crankcase 2 Pry out the oil seal noting the direction of installation See page 3 76 for seal installation 3 Drive the water pump mechanical seal out of the crankcase from inside to outside Note The new mechanical seal must be installed after the crankcases are assembled See Mechanical Seal Installation page 3 77 Polaris Industries Inc 3 73 7 96 ENGINE EH42PL EHS50PL Engine Assembly Crankcase Assembly 1 Remove all traces of gasket sealer from the crankcase mating surfaces Inspect the surfaces Closely for nicks burrs or damage 2 Check the oil pump and oil gallery mating surfaces to be sure they are clean and not damaged Bearing Installation NOTE To ease bearing installation warm the crank case until hot to the touch Place the bearings in a freez er 1 Install the bearings so the numbers are visible 2 Drive or press new bearings into the crankcases using the proper driver CAUTION Press only on outer race of bearing to prevent bearing damage e 70mm 2 755 driver For crankshaft main bearings e 46mm 1 810 For counter balancer bearings e 28mm 1 100 For pump shaft bearing End Play Inspection Adjustment Before reassembling the crankcase the following steps should be performed to determine the amount of crankshaft counter balancer shaft and pump shaft end play Excessive end play may cause engine noise at idle and slow speeds Too little play will side loa
49. d the bearings which may lead to premature bearing failure Crankshaft 1 Make sure all bearings are firmly seated in the crankcase 2 Measure the width of the crankshaft at the bearing seats with a dial caliper or micrometer and record reading 7 96 374 Polaris Industries Inc Assembly Cont 3 Measure the distance from the PTO crankcase mating surface to the main bearing using a dial caliper and a straight edge Subtract the thickness of the straightedge and record Measure the distance from the magneto crankcase mating surface to the main bearing using the same method Remember to subtract the straightedge from the measurement and record Add the readings obtained in step 3 and 4 Subtract the crankshaft width measured in step 2 from the figure obtained in step 5 Subtract the thickness of the existing shim from the result of step 6 to determine if a different shim is needed ENGINE EH42PL EHS5OPL Engine Polaris Industries Inc 3 75 7 96 ENGINE EH42PL EH50PL Engine Assembly Cont Counter Balancer 1 2 Make sure all bearings are firmly seated in the crankcase Measure the width of the counter balancer shaft at the bearing seats with a dial caliper or micrometer and record reading Measure the distance from the PTO crankcase mating surface to the bearing using a dial caliper and a straight edge Subtract the thickness of the straightedge and record Measure the d
50. d u ntil full y S e at e d on the j SAARALEAGGEGGRAGGERGGEAOGEACOEAEERESEECOPESPEEESEESOSUEQSE EY iui base gasket 7 Apply a light film of oil to the threads and flange surface of the cylinder mounting bolts 8 Install all four bolts finger tight Rotate the engine and position the piston at BDC NOTE If cam chain is installed hold it up while rotating the engine to avoid damage to the chain drive sprocket teeth or tensioner blade 9 Tighten the cylinder bolts in three steps in a criss cross pattern and torque to specifications 10 Install the two 6mm bolts Cylinder Head Installation Clean the gasket surfaces on the cylinder head and cylinder Remove all traces of old gasket material Refer to disassembly photos 1 Install the cam chain tensioner guide Be sure bottom vas 1 i ae rine Me ae Guide in end of guide is located properly in crankcase es e recess 2 Install the two dowel pins and a new cylinder head gasket 3 Place the cylinder head on the cylinder Apply a film of engine oil to the cylinder head bolt threads and washers and hand tighten the bolts Polaris Industries Inc 3 81 5 98 ENGINE EH42PL EH50PL Engine Assembly Cont The following procedure must be used to torque the cylinder head properly Cam Chain Camshatft Installation Install the cam chain over the crankshaft with the plated links facing outward CAUTION Serious engine damage may re sult if the camshaft is
51. d upward See text for 4 stroke oil control ring upper rail installation Use the information below to identify pistons and rings Engine Model No re Available Piston Length Standard Piston mm Identification EC25PFE 08 09 10 11 3W 4W 50 EC38PLE 04 05 20 78mm 00 EC38PLE 06 07 20 78mm 38B 50 EH42PL 01 20 66mm 50 EH50PL 01 02 03 29 72mm C 50 Pistons and rings marked 25 equal 25mm 010 oversized Pistons and rings marked 50 equal 50mm 020 oversized Pistons and rings marked 10 equal 1 0mm 040 oversized 250 engines only Polaris Industries Inc 3 3 5 98 ENGINE Engine Specifications EC38PL Engines Jetting Guidelines For Round Port Pistons Pistons for EC38PL engines shipped as service parts have round ports on the intake skirt If you are replac ing an oblong port piston with the new round port style follow the instructions included with the piston or refer to this chart for quick reference Without the jetting change the machine will run slightly rich on the main jet Piston Ports ta ie O O sson This piston was shipped with 1995 amp Late 1996 1 200 Main Jet t mote 1996 een 4 230 Main Jet Intake side Intake side 1 6CEY6 3 Jet Needle A 35 Pilot Jet is not supplied with this piston kit although a 35 is required if you install a round port piston in a 1995 Scrambler EC38PLE 03 engine A round port piston along with the jetting changes shown effectively changes ear
52. ead CMe EERIE STEMS ETETETT Heat ge Inspect mating surface of crankcase and oil pump ao Hiin Matis H Taat Cornea ROR RIIETE A i PAHAMI ha it PETRIATI TITSER ETICII N TEPEE ERIT EREITEA EEEREN CCEE IETECISEEET EREI TE RS f BSartist it fiha BSE ETH pares EEEIEE H HERREN Ent ERAH is i Pere tiin tis hapten as halite Fin nite Het 6 Remove the three screws and strainer screen from pump 7 Clean screen thoroughly Polaris Industries Inc 7 96 ENGINE EH42PL EHS50PL Engine Engine Disassembly Cont 8 Remove pump body screw and feed chamber cover Measure pump end clearance using a thickness gauge and straight edge 10 Measure clearance between outer feed rotor an pump body with a thickness gauge 12 Remove inner and outer feed rotor and pump chamber body 13 Repeat measurements for scavenge rotor 14 Remove inner and outer scavenge rotor and inspect pump shaft for wear 7 96 Polaris Industries Inc ENGINE EH42PL EH50PL Engine Engine Disassembly Cont Oil Pump Assembly 1 Clean and dry all parts thoroughly Apply clean engine oil to all parts Do not use gasket sealer on the pump body mating surfaces or oil passages will become plugged 2 Install pump shaft and scavenge rotor drive pin 3 Install outer scavenge rotor inner scavenge rotor and scavenge casing 4 Install outer feed rotor and inner feed rotor drive pin 5 Install inner feed rotor and
53. ection 3 90 3 91 Sealed Recoil Assembly 0 0 e eee eee 3 91 3 92 Spark Plug Fouling Checklist 22 ic2sccc0c0eev es 3 93 2 Stroke Troubleshooting 2 eee eeee 3 94 4 Stroke Troubleshooting 0 0 e eee ee eee 3 95 3 97 ENGINE Torque Specifications 2 Stroke Engine Torque Specifications Cylinder Head Bolts 250 EC25PFE Ft Lbs kg m 300 EC28PFE Ft Lbs kg m 400 EC38PLE Ft Lbs kg m Tamm ras s28 miesza moes29 Cese o om resa reesza rie esza Camee om seen sen eean 5 0 6 0 5 0 7 5 6 0 7 5 6 0 8mm 8mm 6mm 8 8 8 CAE tem E 585 69 80 Water Pump impelerNut em o ooo 6 7 8 1 0 4 Stroke Engine Torque Specifications Cylinder Head Bolts TINY eae See Engine Assembly for torque procedure page 3 82 6mm See Engine Assembly for torque procedure page 3 82 Cylinder Base Bolts 10mm 45 49 ft Ibs 6 21 6 76 kg m 62 1 67 6 N m 6mm 5 6 ft Ibs 69 828 kg M 6 9 8 28 N m CrankcaSe 0 cee eee 8mm 14 15 ft lbs 2 2 1 93 2 07 kg m 19 3 20 7 N m Cam Chain Drive Sprocket 28mm 35 51 ft Ibs 4 83 7 04 kg m 48 3 70 4 N m Cam Chain Driven Sprocket 6mm 5 6 ft Ibs 69 828 kg m 6 9 8 28 N m Cam Chain Tensioner 6mm
54. er Oil Check Valve Testing 300 The oil pump check valve on the EC28PF engine must be tested by applying 3 7 inches of mercury VACUUM to the line spigot of the check valve The valve should release be tween 3 and 7 inches of mercury Use a Mity Vac PN2870975 or similar vacuum tester The check valve is located on the oil pump Thrust Washer 3083428 not used with plastic drive gear Metal 3083429 Plastic 3084825 gt subs to fe CO Bushing Bushing end play adjustment shims Polaris Industries Inc 3 21 ENGINE EC25PF EC28PF Engine EC25PF Apply 2 7 PSI pres sure to the line fitting To engine 250 400 Check Valve EC28PF Apply 2 7 inches of mercury VACUUM to the line fitting 300 Check Valve Engine oil check valve should release at 2 to 7 PSI Pump Bleed Screw 5 98 ENGINE EC25PF Engine Recoil Disassembly 1 Remove four6mm bolts securing reel housing to flywheel housing NOTE When the last bolt is removed the reel housing will rotate unwinding the recoil spring 2 Remove reel housing NOTE If rope replacement is the only service necessary it may be replaced without any further disassembly 3 Remove pawl return spring 4 Clamp sides of ratchet pawl bracket in the corner of the jaws of a vise Clamp in vise here Use vise 5 Using a cloth belt type strap wrench wrapped around the outside edge of the reel unscrew the reel counterclockwise to remove it from t
55. evel air in system Faulty pressure cap or system leaks Lean mixture restricted jets vents fuel pump or fuel valve Fuel pump output weak Restricted radiator internally or cooling fins Water pump failure Cooling system restriction Cooling fan inoperative Ignition timing misadjusted Low oil level Spark plug incorrect heat range Faulty hot light circuit Thermostat stuck closed Backfiring 7 96 ETC or speed limiter system malfunction Fouled spark plug or incorrect plug or plug gap Carburetion faulty lean condition Exhaust system air leaks Ignition system faulty Spark plug cap cracked broken Ignition coil faulty Ignition or kill switch circuit faulty Ignition timing incorrect Sheared flywheel key Poor connections in ignition system System wiring wet Valve sticking Air leaks in intake Lean condition 3 96 Polaris Industries Inc ENGINE 4 Stroke Troubleshooting EH42PL EH50PL Cooling System Troubleshooting Overheating Insufficient wrong type coolant Air in system Thermostat stuck closed or not opening completely Radiator cap faulty fails to pressurize Restricted system mud or debris in radiator fins or restriction to air flow passages blocked in radiator lines pump or water jacket Water pump inoperative Fan motor inoperative Temperature Too Low Thermostat stuck open Leak at Water Pump Weep Hole Faulty water pump mechanical seal coolant leak Faulty pump shaft oil seal oil leak
56. frame at lower right side of engine near water pump 5 Install upper engine mount bracket to engine and line up all reference marks 6 Align engine by temporarily installing clutches and following alignment offset procedure outlined in the PVT Chapter 7 When engine is aligned properly tighten all engine mounts and install all parts reversing the order of disassembly See engine installation notes Oil Supply 1 Before installing oil supply line add Polaris Premium 4 OW 40 oil to the oil tank until oil flows from feed line 2 Connect the lines to the pump inlet and outlet fitting and Bleed Cooling System SO eS tighten securely Be sure oil feed line is properly connected to the uppermost oil line fitting on the crankcase Add oil until it is at the upper mark on dipstick Fill coolant reservoir tank to full mark With hose removed from thermostat housing add coolant to radiator slowly until coolant begins to flow from thermostat housing Install hose on thermostat housing and tighten clamp Continue to add coolant s ow y until radiator is full Install radiator cap and squeeze coolant lines to force air out of system Remove cap and add coolant if necessary After reassembly is complete start engine and observe coolant level inthe radiator Allow air to purge and top off as necessary Reinstall radiator cap and bring engine to operating temp Check level in reservoir tank after engine is cool and add coolant if necess
57. g Checklist Spark Plug Fouling 2 Stroke Engines Oil pump adjusted incorrectly Adjustment pilot screw Restricted air filter main or pre cleaner Improperly assembled air intake system Oil pump shaft seal leaking fills crankcase Oil pump arm or reel not returning properly cable arm or reel sticking Spark plug cap loose or faulty Choke cable adjustment or plunger cable sticking Foreign material on choke plunger seat or plunger Incorrect spark plug heat range or gap Carburetor inlet needle and seat worn Jet needle and or needle jet worn or improperly adjusted Excessive carburetor vibration loose or missing needle jet locating pins Loose jets in carburetor or calibration incorrect for altitude temperature Incorrect float level setting PVT system calibrated incorrectly or components worn or mis adjusted Fuel quality poor old or octane too high Low compression Restricted exhaust Weak ignition loose coil ground faulty coil stator or ETC switch ETC switch mis adjusted Oil line check valve leaking Spark Plug Fouling 4 Stroke Engines spark plug cap loose or faulty Choke cable adjustment or plunger cable sticking Foreign material on choke plunger seat or plunger Incorrect spark plug heat range or gap Carburetor inlet needle and seat worn Jet needle and or needle jet worn or improperly adjusted Excessive carburetor vibration loose or missing needle jet locating pins Loose jets in carburetor or calibratio
58. haft Oil Clearance Sta 0089 10 mm Camshaft Cam lobe height 1 2884 1 2924 32 726 32 826 mm 1 2884 1 2924 32 726 32 826 mm Limit 1 2766 32 426 mm 1 2766 32 426 mm re s x lt AME aj3 3 1 2884 1 2924 32 726 32 826 mm Limit 1 2766 32 426 mm Camshaft journal OD 1 4935 1 4941 37 935 37 950 mm nee PTO 1 4935 1 4941 37 935 37 950 mm 1 4935 1 4941 37 935 37 950 mm eee PTO 1 4963 1 4970 38 005 38 025 mm 1 4963 1 4970 38 005 38 025 mm Camshaft Oil clearance 0022 0035 055 090 mm Dimi Gylinder Head Surface warpage limi aman Standard height 3 870 98 3 mm Valve Seat Contacting width In 028 7 mm 055 1 4 mm 055 1 4 mm Ex 089 1 0mm O71 1 8 mm Valve Guide Inner diameter 2362 2367 6 0 6 012 mm 2362 2367 6 0 6 012 mm ener Protrusion above head 689 709 17 5 18 0 mm Valve Margin thickness In 039 1 0 mm 039 1 0 mm 0317 8mm Ex 047 1 2 mm 047 1 2 mm 031 8 mm 031 8 mm Valve Stem diameter 2343 2348 5 950 5 965 mm 2341 2346 5 945 5 960 mm Stem oil clearance std 0014 0024 035 062 mm g e 0016 0026 040 067 mm 0016 0026 040 067 mm Limit 0059 15 mm 0059 15 mm Overall length 3 976 101 0 mm 3 976 101 0 mm Free length Orange 1 7342 44 05 mm Paint Yeo
59. he ratchet pawl bracket shaft corner 6 Remove the ratchet pawl bracket spring hook ratchet friction ring and friction spring NOTE Itis not necessary to remove the spring retainer plate and spring unless it is damaged 7 Clean and inspect all parts Repair or replace as required Flywheel Housing Reel Recoil Spring Spring Retaining Plate Seal Spring Hook Ratchet Pawl Pawl Pin Ratchet Friction Ring and Paw Guide 10 Friction Spring 11 Ratchet Paw Bracket 12 Reel Housing 13 Pawl Return Spring 14 Recoil Rope 15 Rope Handle 16 Recoil Cup 17 Timing Plug 18 Bushing Oe ee 7 96 3 22 Polaris Industries Inc ENGINE EC25PF Engine Recoil Assembly 1 Ifthe recoil spring was removed reinstall it in its recess in the flywheel housing The spring should spiral counterclockwise toward the center 2 Grease spring with Polaris low temperature grease 3 Install recoil spring retaining plate 4 Grease and install spring hook making sure it properly engages the spring end 5 Install ratchet friction ring and friction spring Pin must engage assembly The friction spring should engage the hole during bent tab on the recoil spring retaining plate The L eg N asseimbly on the friction ring should be positioned as shown in the photo at right 6 Grease the center hole and seal in the flywheel housing 7 Install ratchet pawl bracket The alignment pin and the square drive on the b
60. hrust washer from pump shaft Fik a a 2 Remove pump drive gear Inspect drive gear teeth for cracks damage or o excessive wear a eo er eee torre OREIN EEEIEE AER C g Viiaststar Wind ot Phi in heist ree etate prrerertyy it if ts CORR j CRE S ia FRIETEN Nae iste dit state ort RETETE H HA AA AA iph Nay AAEPEIRANAPRAPPB PAPAIHIA PAINIAR RE ianiai eet eedenendtid srasiisteasdeastistl vectiiestis st PROTEC INET R TIRT Yee Tadd POTENT UICC EET IT hs ETT any STIRS CSET CERIO ERI CD Psat tapas RATTET Hi 4 Remove three oil pump retaining bolts and pump a hi i As brtindsde reyes PEAT TINTAREN y i ETETE ahn hay i Anina inuitidnantendeeadnat abd Aen APAP Ads PranndribA tT cent tti AHNA MANAN VETETTE CESERIS ST ORESIC MODI OSES TETIRETIRITTER T TEETE AAT AMMA RRtAritat reterii TNT Att RINT caer i TSS ITERE T PERDAR SOAR TT y SUR RSE Tis it By hti TILILA SEITETE TETEE EETRI SEINE Badger TRS Ea et snaha ERE RT SO an NIU OTE ENTS POM MRE EST TPES Sire PUARE IA aE EARED ne ERAT Li OMT An On Cr sn STS Nan a Hearke PAREI Oe TERTARIK AEET E g PEITA EEEE EERI AITTTIR TETTERE Haha ih gt p ST NORITTIRTC EN CREST Ie TT ny IA IMBA AA AIAH DA Ain Mm 44 H H COI hn PASSES Pees steayssces viata vedas ral i amp H 5 TSS ERENER STOPS et sot Har Teer EE eRe tiiit Check for nicks burrs or surface irregularities nna n HENE ttt SLT Convery tes RCC I i b
61. ies Inc ENGINE EH42PL EH50PL Engine Engine Disassembly Cont Flywheel Stator Removal Inspection 1 Remove flywheel nut and washer 2 Install flywheel puller PN 2870159 and remove flywheel CAUTION Do not thread the puller bolts into the flywheel more than 1 4 or stator coils may be damaged 3 Mark or note position of stator plate on crankcase 4 Remove bolts and carefully remove stator assembly being careful not to damage crankshaft bushing or oil seal on stator plate 5 Remove oil passage O Ring 6 Remove large sealing O Ring from outer edge of stator plate Cam Chain Tensioner Blade 1 Remove bolt securing tensioner blade to crankcase 2 Remove blade and inspect for cracks wear or damage 3 Removecam chain Inspect chain for worn or missing rollers or damage Stretch chain tight on a flat surface and apply a 10 Ib 4 53 kg load Measure length of a 20 pitch section of chain Replace if worn past service jl Heath Polaris Industries Inc 3 67 7 96 ENGINE EH42PL EH50PL Engine Engine Disassembly Cont 4 Using the special socket remove the crankshaft slotted nut NOTE The slotted nut is a left hand thread 5 Remove cam chain drive sprocket and Woodruff key from crankshaft Inspect sprocket teeth for wear or damage Inspect Woodruff key for wear Replace any worn or damaged parts One Way Valve The one way valve prevents oil from draining out of the o
62. ies Inc 3 25 7 96 ENGINE EC38PL Engine Disassembly Cont 7 Remove flywheel using Polaris flywheel puller 8 Remove stator assembly Reassembly Note During reassembly be sure to seal rubber grommet A completely with silicone sealer to avoid water or dirt ingestion into stator as sembly 150 Watt alternator shown at right photo 2 200 Watt alternator shown at right photo 3 9 Remove six cylinder head bolts using a 12 mm socket Note the position of the bleeder plug for the coolant system 10 96 3 26 Polaris Industries Inc ENGINE EC38PL Engine Disassembly Cont 400L Head Gasket pictured at right Reassembly Note The 400L head gasket should have the word UP B toward the cylinder head and the tab C toward the exhaust matching the tab area on the cylinder NOTE Small hole in cylinder above exhaust portis a decompression aid for starting 10 Loosen clamps retaining coolant transfer hose and remove the four cylinder nuts NOTE Usea 14 mm socket on the exhaust side A 14 mm wrench will be necessary on the intake side Reassembly Note Due to limited space you will need to use a crows foot adaptor for final torquing during reassembly 11 Install piston support block and remove C clips Reassembly Note When reinstalling C clips make sure that the open end of the retainer clip points either up or down not to the side Polaris Industries Inc 3 2 10 96 ENGINE EC38PL E
63. il tank and into the crankcase when the engine is off It must be clean and have adequate spring pressure in order to seal properly 1 Remove cap bolt sealing washer spring and one way valve from PTO side crankcase 2 Inspect free length of spring and check coils for distortion 3 Inspect valve for wear 4 Check seat area for nicks or foreign material that may prevent proper sealing of valve Crankcase Separation 1 Remove flange bolts 10 from magneto side crankcase evenly in a criss cross pattern 2 Install crankcase puller tool on magneto side crankcase with hole positioned over balancer gear NOTE The flywheel key must be removed before puller is installed 3 Separate crankcase by tightening puller bolt in small steps and tapping on the pump shaft lightly with a plastic hammer 4 Tap lightly on balancer gear with a brass drift through the hole in the puller if necessary to ensure the balancer shaft stays in the PTO side crankcase 5 Continue to tighten puller center bolt while tapping on pump shaft and balancer shaft until cases are separated 7 96 3 68 Inspect for Areas of Tooth Wear or Damage Polaris Industries Inc ENGINE EH42PL EH50PL Engine Engine Disassembly Cont Oil Pump Removail Inspection tt Uren traeetsieomnseinrsrerranrestereierer inerirreecist ere eer tt ANA AIAIEL AA LBL ALLE SUS ga TEgBEU BEL LAABEEES Cas g AA TAAR Meihana iianhnaitiiaeettepeeeata aiie Remove t
64. is Industries Inc Recoil Disassembly Inspection Cont 5 6 Slowly remove spring tension by rotating reel clockwise until all tension is removed Remove 6 mm bolt and spring washer securing friction plate Remove friction plate Inspect plate for wear or damage Inspect plate friction spring for wear damage and proper tension The spring should fit tightly on friction plate Remove ratchet pawl with spring and inspect Replace spring or ratchet pawl if worn broken or damaged Slowly and carefully remove reel from recoil housing making sure the spring remains in the housing Inspect the reel hub and bushing for wear Unwind rope and inspect for cuts or abrasions Inspect drive tab on hub return spring for damage To remove hub return spring hold outer coils in place with one hand and slowly remove spring one coil ata time from the inside out Recoil Assembly CAUTION Be sure to wear a face shield and eye protec tion when performing this procedure To install a new spring 1 Zs Place spring in housing with the end positioned so the spring spirals inward in a counterclockwise direction see photo above Hold spring in place and cut retaining wire To reinstall an old spring 3 Hook outer tab in place in recoil housing and wind spring in a counterclockwise direction one coil ata time while holding the installed coils in place Lubricate the spring with light lubricant such as Polaris Cable
65. istance from the magneto crankcase mating surface to the bearing using the same method Add the readings obtained in step 3 and 4 Subtract the counter balancer shaft width measured in step 2 from the figure obtained in step 5 Subtract the thickness of the existing shim from the result of step 6 to determine if a different shim is needed Pump Shaft Make sure the pump shaft bearing is firmly seated in the Magneto side crankcase Measure the distance from the magneto crankcase mating surface to the bearing using a dial caliper and a straight edge Subtract the thickness of the straightedge and record Install the gear on the oil pump and measure the width of the pump and gear Subtract this measurement from the measurement recorded in step 2 Subtract the thickness of the existing shim from the result of step 3 to determine if a different shim is needed Pump Shaft Oil Seal Installation Ts 2 Install the seal from the outside of the crankcase water pump side with the spring facing inward toward the pump shaft bearing Drive or press the seal into place using the 25mm 985 seal driver until flush with the bottom of the mechanical seal bore Lubricate the seal lip with grease 7 96 3 76 Polaris Industries Inc ENGINE EH42PL EH50PL Engine Assembly Cont Crankshaft Counter Balancer and Oil Pump Installation Lubricate all bearings with clean engine oil before assembly See engine disassembly photo
66. k Cover e Fuel Tank See Fuel System Chapter 5 Disconnect oil pump cable 2 Strokes 6 Disconnect spark plug high tension lead 7 Remove springs from exhaust pipe and remove pipe 8 Remove air pre cleaner and duct 9 1 1 A a a Remove airbox 0 Remove carburetor 1 Inserta shop towel into the carburetor flange to prevent dirt from entering the intake port 12 Loosen auxiliary brake adjuster locknut remove adjusting bolt and brake actuator arm 13 Remove center chain guard bolt two screws and chain guard on AWD models 14 Remove center drive and driven sprocket bolts and remove chain and sprockets as an assembly 15 Refer to PVT section page 6 9 for procedure to remove inner PVT cover 10 96 3 8 Polaris Industries Inc Engine Removal Preparation Cont 16 Starter motor Note ground cable location Mark positive cable mounting angle and remove cable 17 Remove transmission linkage rods from shift selector and secure out of the way 18 Disconnect coolant temp sender wire where applicable 19 Remove nut ground cable and washer from the upper right engine mount 20 Remove the two upper engine mount plate bolts and remove the plate and ground cable where applicable 21 Remove nut and washer from lower front engine mount 22 Loosen nut on slotted rear engine mount plate and back it out to the end of the stud Polaris Industries Inc 3 9 ENGINE Engine Removal 7 96 ENGI
67. k and forth through bearing while rotating and check for rough spots 4 With pin and bearing centered in rod twist ends back and forth in all directions to check for excessive axial play Pull up and down evenly on both ends of pin to check for radial play Replace pin and bearing if there is any resistance to rotation or excessive axial or radial movement If play or roughness is evident with a new pin and bearing replace the connecting rod 10 96 3 34b Polaris Industries Inc ENGINE EH42PL EH50PL Engine Exploded View Crankcase Cylinder Cylinder Crankshaft ZZ Valve Train and Piston Polaris Industries Inc 3 35 7 96 ENGINE EH42PL EHS50PL Lubrication Oil Flow Engine Lubrication DAR a E E ee 2 Polaris Premium 4 Syntheti PN 2871281 or API certified SH 5W30 oil Capacity 000 eee 2 U S Quarts 1 9 1 INCE ina tex oad enw eeaw be Babes PN 3084963 Filter Wrench Snap On PN YA997 or equivalent Drain Plug Torques 14 ft Ibs 1 9 kg m tank and sump Oil Pressure Specification 20 PSI 5500 RPM Polaris OW 40 Synthetic Engine Hot Oil Flow The chart on page 3 37 describes the flow of oil through the engine Beginning at the oil tank the oil flows through a screen fitting in the bottom of the tank and into the oil supply hose The feed side of the oil pump draws oil through the hose and into the crankcase oil gallery and then pumps the oil through another pass
68. k tank EH42PL EH50PL Oil Flow Chart Top of Oil Tank Union Fitting Lower Oil Gallery Scavenging Screen Fitting Bottom of Tank Small End Bearing Cylinder Sleeve Main Bearing PTO Chain R Sprocket Indirect Lubrication a Large End Bearing Crankshaft Stator Plate Bushing Oil Jet Through Cylinder Stud Front Left Delivery Pipe Crankcase Delivery Pipe Oil Gallery 3 37 10 96 ENGINE EH42PL EHS50PL Engine Removal The following components can be serviced or removed with the engine installed in the frame e PVT System e Flywheel Alternator Stator e Starter Motor Starter Drive Camshaft e Rocker Arms e Cam Chain and Sprockets e Cam Chain Tensioner and Guides e Cylinder Head e Cylinder e Piston Rings The following components require engine removal for service e Oil Pump Water Pump Water Pump Mechanical Seal Counterbalancer Assembly e Connecting Rod e Crankshaft e Crankshaft Main Bearings e Crankcase Complete engine removal is not necessary to inspect or replace the water pump impeller Engine Removal Preparation a eS 2S SS Clean work area Thoroughly clean the ATV engine and chassis Disconnect battery negative cable Drain oil tank and engine sump Remove the following parts Refer to the Body Chapter for removal procedures Seat e Left and Right Side Covers Fuel Tank C
69. lier model EC38PL engines to 1997 spec ifications for carburetion and engine operating characteristics Jetting compensation for altitude and temperature will be the same as 1997 EC38PLE 06 engines or EC38PLE 07 Sport Scrambler engines TIn all cases the 6CEY6 3 Jet Needle included with piston should be installed if you replace an oblong port style piston with a round port style piston Standard E clip position is 3 Year Engine Type Original Original Main Need to Change Main Jet Piston fe NO Use NO Use Original T NO Use Original Sse pe F NES pe 230 Main Jet YES Use ont 135 Pilot det 4002 2x4 ETT AA Sponsinan 400 6x6 VES 20th Main Jer oie 400 Xplorer at Round Pons NOW es Onna P 4x4 400 6x6 ij 250 1 _YES Use 2 230 Main Jet T Late ECSSPLE 05 Soars ax Scrambler Tnd Ports NO Use Giana 1996 1997 EC38PLE 06 Xpress 400 Xplorer 400 Round Ports NO Use Original Sportsman 4x4 400 6x6 EC38PLE 07 Sport 400 Scrambler 4x4 Round Ports NO Use Original Late ECSBPLE 04 1996 Polaris Industries Inc 3 3a 5 98 ENGINE Engine Specifications NOTES 5 98 3 3b Polaris Industries Inc ENGINE Service Data EH42PL EH50PL Engine Service Data Rocker Arm Rocker arm 1D Rocker shaft OD 8656 8661 21 987 22 0 mm 8656 8661 21 987 22 0 mm Rocker s
70. low air to purge and top off as necessary Reinstall radiator cap and bring engine to operating temp Check level in reservoir tank after engine is cool and add coolant if necessary Transmission 1 Readjust transmission shift linkage as outlined in Transmission Chapter page 8 3 Exhaust 1 Replace exhaust gaskets Seal connections with high temp silicone sealant 2 Check to be sure all springs are in good condition Engine Break In Period 2 Strokes 1 Pre mix first tank of fuel at a 40 1 ratio with Polaris Premium Synthetic 2 Cycle Lubricant Verify proper oil usage from oil tank during the first tank of fuel 2 Avoid prolonged idle or periods of sustained full throttle Vary throttle settings Polaris Industries Inc 3 11 10 96 ENGINE EC25PF EC28PF Engines Disassembly 1 Remove the flywheel nut and flywheel with Flywheel Puller PN 2871043 Remove stator assembly 2 Remove cylinder head and cylinder Remove piston pin clips Use Piston Pin Puller PN 2870386 to remove piston pin from piston 3 Inspect connecting rod small end and bearing piston piston pin cylinder bore as shown on page 3 33 3 34b 4 Remove the crankcase half attaching bolts Heat crankcase in the bearing support areas After applying heat tap on PTO end and magneto end to separate case half from crankshaft 5 After removing the crankshaft thoroughly clean the bearings and lubricate Check bearing condition by pressing on and rot
71. lve Timm 14 19 ft lbs 1 93 2 62 kg m 19 3 26 2 N m Stator Plate 6mm 5 6 5 ft Ibs 69 897 kg M 6 9 8 97 N m FIVWNES enpiri EnEn 16mm 58 72 ft Ibs 8 00 9 94 kg m 80 0 99 4 N m Starter Motor 6mm 5 6 5 ft Ibs 69 897 kg M 6 9 8 97 N m Recoil Housing 6mm 5 6 5 ft Ibs 69 897 kg m 6 9 8 97 N m Spaik PIUO spacer crane ceebaeee sede whes 14 ft bS 245s hanes 1 94 kKg M ooa 19 4 N m Polaris Industries Inc 3 1 5 98 ENGINE Engine Fastener Torque Patterns When torquing nuts bolts and screws a specific pattern should be followed to ensure that all parts are tigntened evenly The correct amount of turning force or tightness is determined by a torque wrencn which is broken down into either inch or foot pounds e 2 as O O a Cylinder Head Cylinder Head Cylinder Base 250 300 400 250 300 400 Pq O OOG 3 4 Q O Cylinder Base Crankcase Crankcase 425 500 400L 250 300 O Q Refer to page 3 82 for torque procedure Cylinder Head 425 500 10 96 3 2 Polaris Industries Inc ENGINE Engine Specifications 1996 to Current Engine Specifications Machine Model Engine Disp Bore Stroke mm Ring End Piston Clearance Engine Op Model mm in in Gap Clearance Svc Limit erating i
72. ly on tensioner body with a soft face hammer and remove tensioner Cam Chain Tensioner Inspection 1 Pullcam chain tensioner plunger outward to the end of its travel Inspect teeth on ratchet pawl an plunger for wear or damage 2 Push ratchet pawl and hold it The plunger should move smoothly in and out of the tensioner body TDC Mark Rotation nal Advance Marks Polaris Industries Inc 10 96 3 44 ENGINE EH42PL EHSOPL Engine Engine Disassembly Cont 3 Release ratchet pawl and push inward on plunger It should remain locked in position and not move inward 4 Measure free length of tensioner spring Replace spring if excessively worn 5 Replace entire tensioner assembly if any part is worn or damaged Rocker Arm Shaft Removal 1 Loosen rocker shaft retaining bolt 2 Remove the four bolts securing rocker shaft supports and remove the supports rocker shaft and rocker arms as an assembly being careful not to drop the dowel pins into the engine Rocker Arm Shaft Inspection 1 Remove retaining bolt from the PTO left end rocker shaft support 2 Mark or tag intake rocker arms so they can be installed in the same position 3 Inspect each rocker arm cam follower surface If there is any damage or uneven wear replace the rocker arm NOTE Always inspect camshaft lobe if rocker arms are worn or damaged i aaaea aaa aauaaaaaaaaaaaaaaaaaaaaaaualalull ll llllalalaaalls l ll l l
73. n mm in mm in mm RPM Trail Blazer EC25PFE 09 11 244 72 2 8346 60 2 362 009 018 0011 0021 006 5800 Trail Boss EC25PFE 08 10 23 46 03 05 15 6000 Xpress 300 EC28PFE 01 283 74 5 2 935 65 2 561 012 022 0012 0026 006 5600 Xplorer 300 02 31 56 03 07 15 300 Xpress 400 EC38PLE 379 83 3 270 70 2 758 007 015 0023 0037 006 5700 Xplorer 4x4 04 06 18 38 06 09 15 Sportsman 400 400 6x6 Sport EC38PLE 379 83 3 270 70 2 758 007 015 0023 0037 006 5700 Scrambler 400 05 07 09 18 38 06 09 15 6000 Magnum 2x4 EH42PLE 425 87 9 3 461 70 2 758 008 0006 0018 0024 6000 Magnum 4x4 01 02 20 015 046 061 Magnum 6x6 Sportsman 500 EH50PLE 498 92 3 622 75 2 953 008 015 0006 0018 0024 6000 Xplorer 500 01 05 06 07 20 38 015 046 061 Big Boss 500 6x6 Scrambler 500 EHSOPLE 02 498 92 3 622 75 2 953 008 015 0006 0018 0024 6000 04 20 38 015 046 061 Piston Identification Note the directional and identification marks when viewing the pistons from the top The letter F gt or must always be toward the flywheel side of the engine The other numbers are used for identification as to diameter length and design Two stroke rings are keystone design Four stroke engine rings are rectangular profile The numbers or letters on all rings except 4 stroke oil control rings must be positione
74. n incorrect for altitude temperature Incorrect float level setting PVT system calibrated incorrectly or components worn or mis adjusted Fuel quality poor old or octane too high Low compression Restricted exhaust Weak ignition loose coil ground faulty coil stator or ETC switch ETC switch mis adjusted Restricted air filter main or pre cleaner Improperly assembled air intake system Restricted engine breather system Oil contaminated with fuel Restricted oil tank vent Polaris Industries Inc 3 93 10 96 ENGINE 2 Stroke Engine Troubleshooting Condition Possible Cause _Action Possible Cause Add fuel as required Clean line replace filter Clean or replace valve as necessary No fuel Dirt in fuel line or filter Engine turns over but does not start Fuel will not pass through on off valve petcock Tank vent plugged Carb starter circuit Engine flooded Low compression below 100 PSI at sea level No spark Dead battery Starter motor does not turn Engine does not turn over Engine stuck Plugged carb pilot system Carb misadjusted Engine runs but will not idle Choke not adjusted properly Low compression Crankcase leak Broken throttle cable Obstruction in air intake Incorrect carb jetting Engine idles but will not rev up Reverse speed limiter limiting speed Incorrect ignition timing Restricted exhaust system Cylinder piston and ring wear or d
75. ne damage Polaris Premium 60 40 Antifreeze Coolant is recommended for use in all cooling systems and Forward comes pre mixed and ready to use aA Some models add spacer PN 5211809 between fan motor bracket and frame Cooling System Specifications Liquid Cooled 250 300 Scrambler and Sport Except Scrambler and Sport F C Fan Switch Off 210 F 99 C 10 154 F 68 C 5 175 F 79 C 5 Fan Switch On 235 F 113 C 174 F 79 C 190 F 88 C E A Hot Light On 2 Strokes D 205 F 96 C 205 F 96 C System Capacity 2a 2 25 Quarts 2 25 Quarts Radiator Cap Relief 13 PSI 13 PSI Pressure Polaris Industries Inc 3 7 5 98 Hot Light On 4 Strokes ENGINE 2 Stroke Engine Removal The following components can be serviced or removed with the engine installed in the frame e Flywheel e Alternator Stator e Starter Motor Starter Drive e Cylinder Head e Cylinder e Piston Rings e Oil pump 250 400L e Counterbalancer Assembly 400L engines e Water pump The following components require engine removal for service Connecting Rod e Crankshaft e Crankshaft Main Bearings e Crankcase e Oil pump 300 Engine Removal Preparation Typical 2 Stroke Clean work area Thoroughly clean the ATV engine and chassis Disconnect battery negative cable Remove the following parts Refer to the Body Chapter for removal procedures e Seat Left and Right Side Covers e Fuel Tan
76. ne to left until the coolant supply hose clamp clears the frame at the water pump fitting 2 Lift and twist engine clockwise until the lower left engine mount stud is clear of the frame mount and the lower right coolant hose clamp clears the frame tube 3 Support engine in this position with a suitable support such as a board or a 2x4 4 Place a drain pan beneath area to catch coolant 5 Clamp coolant inlet hose leading from radiator to pump to reduce coolant spillage 6 Loosen hose clamp on upper water pump outlet coolant hose and remove hose draining engine coolant into container NOTE Remove plug in thermostat housing to increase flow 7 Reinstall hose and clamp 8 Remove hose from water pump inlet and place in container Release clamp from hose and allow hose to drain completely 9 Lift back of engine while rotating front of engine clockwise and remove engine from left side of frame 7 96 3 42 Polaris Industries Inc ENGINE EH42PL EHS50PL Engine Engine Installation 1 Install engine from left side of frame placing slotted rear engine plate in position with washer and nut on top of plate 2 Attach water pump inlet hose and tighten clamp 3 With engine in place on rear mount and inlet hose connected tip top of engine to the left and rotate counterclockwise to engage lower left engine mount in frame 4 Continue rotating engine making sure the hose clamp for the water pump inlet hose clears the
77. neto end crankshaft main bearing The one way valve is located on the front left PTO side of the crankcase The valve prevents oil in the tank from draining into the engine sump when the engine is off The valve mechanism consists of a plunger return spring guide plug and sealing washer When the engine is running oil pressure lifts the plunger off the seat allowing oil flow When the engine is off spring pressure forces the plunger against the oil passage seat preventing oil flow from the tank to the sump The one way valve requires very little maintenance If engine oil drains into the sump when the engine is off inspect the valve sealing surface for debris or damage Inspect the return spring for distortion or damage Oil Pressure Test 1 Remove blind plug on front left cylinder head 2 Insert a 1 8 NPT oil pressure gauge adaptor into the cylinder head and attach the gauge 3 Start engine and allow it to reach operating temperature monitoring gauge indicator 1 96 3 36 Polaris Industries Inc Union Fitting Upper Prevents oil from draining into crankcase with engine off Internal passage to camshaft front left head bolt Oil Pump Feed One Way Valve Delivery Pipe Polaris Industries Inc ENGINE EH42PL EH50PL Engine Oil filter Oil feed to filter From filter to crankshaft One way valve Top fitting is oil Bottom fitting is oil feed or intake exhaust or return from bottom of to tan
78. ng installed gap after re boring a cylinder or when installing new rings A re bored cylinder should always be scrubbed thoroughly with hot soapy water rinsed and dried completely Wipe cylinder bore with an oil rag immediately to re move residue and prevent rust Crankcase Disassembly NOTE Engine must be removed from frame to disas semble crankcase Refer to engine removal pages 3 38 3 42 Remove the following components cylin der head cylinder water pump impeller NOTE The recoil starter starter motor starter drive flywheel stator cam chain and sprockets can be serv iced with the engine in the frame Polaris Industries Inc 3 65 7 96 ENGINE EH42PL EH50PL Engine Engine Disassembly Cont Starter Drive Removal Inspection 1 Remove recoil housing bolts and remove housing 2 Remove starter drive assembly Note the thrust washer located at the rear of the drive mechanism 3 Inspect the thrust washer for wear or damage and replace if necessary 4 Measure the OD ofthe starter drive shaft on both ends and record 5 Measure the ID of the bushing in the recoil housing and in the crankcase and record Measure in two directions 90 apart to determine if bushing is out of round Calculate bushing clearance Replace bushing if clearance exceeds the service limit 6 Inspect gear teeth on starter drive Replace Starter drive if gear teeth are cracked worn or broken 7 96 2 66 Polaris Industr
79. ngine Disassembly Cont 12 Remove piston pin using Polaris piston pin puller PN 28703886 Use on 1994 Piston Ports 1995 amp Early 1996 Use same style pis Intake side tan as was removed Piston Ports O O Use on Late 1996 to current Intake sid 13 Remove slotted eft hand thread crankshaft nut using Polaris tool PN 2870967 Reassembly Note Reinstallation of this crankshaft nut will also require use of tool PN 2870967 14 Remove five crankcase bolts A with a 12 mm socket 15 Remove four nuts and two bolts B indicated in the photo at right with a 10 mm socket 16 Remove cover tapping lightly with a soft face hammer if necessary 17 Using a 10 mm socket remove the impeller nut C 18 Slide water pump assembly from counterbalance assembly Reassembly Note Watch for adjuster shims which may be between the impeller and pump housing Make sure to reinstall any shims removed Apply Loc tite 242 to impeller nut 10 96 3 28 Polaris Industries Inc ENGINE EC38PL Engine Disassembly Cont 17 Remove collar O ring guide washer and crankshaft gear A NOTE A large screwdriver may be used to aid removal 18 Remove two bolts retaining the counter balance bracket B using a 10 mm socket CAUTION Make no attempt to remove the counterbalance until steps 17 and 18 are complete or damage may result to the counterbalance assembly Reassembly Note Punch marks C
80. oning Procedure Selecting a hone which will straighten as well as remove material from the cylinder is very important Using a common spring loaded finger type glaze breaker for honing is never advised Polaris recommends using a rigid type hone which also has the capability of oversizing Two manufacturers of this type of hone are Sunnen Prod ucts Company of St Louis Missouri and Ammco Tools Inc of North Chicago Illinois The photo at right shows the Ammco No 3950 hone Cylinders may be wet or dry honed depending upon the hone manufacturer s recommendations Wet honing re moves more material faster and leaves a more distinct pat tern in the bore It is important that the cylinder be thoroughly cleaned after honing to remove all grindings which could cause piston or cylinder damage Wash the cylinder in a solvent then in hot soapy water rinse blow dry and oil lightly NOTE Honing material may become trapped in rough cast ing areas such as the area between the cylinder sleeve and port openings Use electrical contact cleaner to ensure these areas are clean A finished cylinder should have a cross hatch pattern to aid in the retention of the fuel oil mixture in the initial break in 1 Wash cylinder with solvent 2 Using a vise clamp cylinder around the exhaust port studs NOTE Protect from vise jaw serrations with brass stock wood or cardboard 3 Place hone in cylinder Tighten stone adjusting knob until the
81. or a dial bore gauge Measure bore 1 2 down from top of cylinder in two directions in line with piston pin and 90 to the pin to determine if bore is out of round Re peat measurements at bottom of cylinder to determine taper or out of round at the bottom Record all mea surements Piston Inspection Measurement Generic 1 Check piston for scoring or cracks in piston crown or pin area Excessive carbon buildup below the ring lands is an indication of piston ring or cylinder wear 2 Measure piston outside diameter at a point 10 mm 3 8 up from bottom of skirt at a 90 angle to the direction of the piston pin Record the measurement NOTE The piston must be measured at this point to pro vide accurate piston to cylinder clearance measure ment 3 Subtract this measurement from the maximum cylinder measurement recorded previously If clearance exceeds the service limit determine if piston or cylinder is worn and recondition or replace as necessary Refer to page 3 3 for piston to cylinder clearance specifications 10 96 3 34 Polaris Industries Inc ENGINE Disassembly Inspection Polaris Piston Ring Installed Gap _ Position each piston ring 1 2 1 3 cm from the top of the cylinder using the piston to push it squarely into place Measure installed gap with a feeler gauge at both the top and bottom of the cylinder ENITI Pe Poo Ta BAE OAS yH ee H NOTE A difference in end gap between the bottom
82. orward WARNING Never remove radiator cap when en gine is warm or hot The cooling system is under pressure and serious burns may result Allow the engine and cooling system to cool before servicing wae Here 1 Remove radiator cap access panel from front of headlamp housing Remove recovery bottle hose from radiator Connect a Mity Vac PN 2870975 to radiator and pressurize system to 10 PSI The system must retain 10 lbs of pressure for five minutes or longer lf pressure loss is evident within five minutes check radiator all cooling system hoses and clamps or water pump seal Radiator Cap Pressure Test 1 Remove radiator cap and test using a cap tester Commercially available 2 The radiator cap relief pressure is 13 Ibs for all models 3 6 Polaris Industries Inc ENGINE Cooling System 5 Blade Fan Air Cooled Models Fan assembly shown is 6 Blade Fan Liquid Cooled Models for air cooled models Raised side of reinforcement rib faces engine on air cooled and liquid cooled Red dot faces engine Washer used here on metal fan blades Sportsman 500 Recommended Coolant Soll Use only high quality antifreeze coolant mixed with dis tilled water in a 50 50 or 60 40 ratio depending on freeze protection required in your area CAUTION Using tap water in the cooling system will lead to a buildup of deposits which may restrict coolant flow and reduce heat dissipation resulting in possible engi
83. over e Fuel Tank see Fuel System Chapter e Rear Rack e Rear Cab Disconnect spark plug high tension lead Remove air pre cleaner and duct Disconnect engine breather line from engine Hold plastic fitting on airbox LH side with a wrench remove oil tank breather line clamp and remove line Loosen carburetor boot clamp and two bolts securing airbox Remove airbox 7 96 3 38 Polaris Industries Inc ENGINE EH42PL EHS50PL Engine Removal Cont 11 Remove carburetor 12 Insert a shop towel into the carburetor flange to prevent dirt from entering the intake port 13 Remove springs from exhaust pipe and remove pipe AWD Models 14 Loosen auxiliary brake adjuster locknut remove adjusting bolt and brake actuator arm 15 Remove center chain guard bolt two screws and chain guard 16 Remove center drive and driven sprocket bolts and remove chain and sprockets as an assembly PVT Disassembly All Models 1 Remove the screws and retainer clips from PVT outer cover and remove cover 2 Mark the drive belt direction of rotation and remove drive belt The belt is normally installed so the numbers can be easily read 3 Remove drive clutch retaining bolt and remove drive clutch using puller PN 2870506 4 Remove driven clutch retaining bolt and driven clutch using puller PN 2870913 5 Remove driven clutch offset spacers from the transmission input shaft 6 Remove cable tie from PVT air outlet duct
84. p rall has a locating tab to prevent rota tion The tab must be positioned in the notch on the side of the piston as shown 7196 3 78 Polaris industries inc ENGINE EH42PL EHS50PL Engine Assembly Cont 3 Install the bottom rail with the gap at least 30 from the end of the expander on the side opposite the top rail gap See Ill Ring Profile 4 Install the second ring with the R mark facing up Position the end gap toward the rear intake side of the piston 5 Install the top ring chrome faced with the R mark facing up and the end gap facing forward toward the exhaust See Ill 6 Check to make sure the rings rotate freely in the groove when compressed Piston Installation 1 Clean the gasket surfaces on the cylinder and crankcase Remove all traces of old gasket material 2 Make sure the cylinder mounting bolt holes are clean and free of debris Second 3 Install a new circlip on one side of the piston with the end gap facing up or down and tang outward CAUTION Circlips become deformed during the removal process Do not re use old circlips Do not compress the new clip more than necessary upon installation to prevent loss of radial tension Severe engine damage may result if circlips are re used or deformed during installation 4 Apply clean engine oil to the piston rings ring lands piston pin bore piston pin and piston skirt Lubricate the connecting rod both ends
85. r If PTO end bearings have not yet been installed mea sure distance as shown in photo at right then pro ceed to Step 2 2 Measure distance from crank wheel to bearing seating surface A Record measurement Wank Rj Benene tiiti gt saaana assnatannanena annann nn pa nran TETEE ONIDOOEOOEEOUD IDURD DUDI DOREN E EE PEENEPETEEEEE EEEEEEEEEEEe Eeee 5 98 3 14 Polaris Industries Inc ENGINE EC25PF EC28PF Engines Assembly Cont Correct crankshaft end play is 008 016 2 4 mm End play is adjusted by adding or subtracting spacer washers from between the inner PTO end bearing and the crank wheel Two different thickness spacers are avail able for EC 25 and EC28 engines For all EC25PF except late 1998 PN 3083629 008 2 mm and PN 3083630 004 1 mm For late 1998 EC25PF and All EC28PF PN 3084778 008 2 mm and PN 3084779 012 3 mm 3 Measure width of main bearing outer races with bearings positioned as shown Add the thickness of the spacer between the bearings if applicable Record measurement 4 Add all recorded measurements from Steps 1 2 and 3 and record the total on line A below If PTO bearings were assembled on crankshaft record the measurement from Step 1 5 Measure PTO crankcase half as shown to determine depth of case Place a piece of flat stock on the case mating surface and measure from this surface to the bearing seating surface Subt
86. racket shaft should properly align in the spring hook 8 While holding the bracket tight against the spring hook flip the flywheel housing over and thread the reel onto the pawl bracket shaft 9 Clamp the ratchet pawl bracket in the corner of the jaws of a vise Firmly hand tighten the reel 10 If the rope was removed or if a new rope is being installed attach one end of the rope to the reel pass the other end of the rope through the guide in the reel housing and attach it to the rope handle 11 Install the rope housing over the reel 12 Holding the flywheel housing with one hand rotate the rope housing clockwise until the rope is completely re wound 13 Rotate the housing three more turns and reinstall bolts 14 Reinstall pawl return spring 15 Check recoil and ratchet operation 16 When reinstalling assembly onto engine use Loctite 515 Gasket Eliminator between the flywheel housing and crankcase Polaris Industries Inc 3 23 7 96 ENGINE EC25PF Engine Recoil Assembly The recoil cup is incorporated onto the flywheel 1 Ifthe recoil rope was removed or if a new rope is being installed attach one end of the rope to the reel pass the other end of the rope through the guide in the reel housing and attach it to the rope handle 2 Install the rope housing over the reel 3 Holding the flywheel housing with one hand rotate the rope housing clockwise until the rope is completely re wound 4 Rot
87. ract thickness of flat stock and record the measurement on line B below 6 Measure magneto side case half using the same procedure Record measurement on line C below Remember to subtract thickness of flat stock 7 Add the readings from steps 5 and 6 and record on line D Subtract line A from line D The result is the amount of crankshaft end play 8 If adjustment is required determine the amount of spacers needed to achieve proper end play Install spacers on crankshaft followed by PTO bearings Connecting Rod Side Clearance Total from Step 1 2 and 3 or from Step 1 only if PTO 1 Measure clearance between lower rod and bearings were installed A counterweight with a feeler gauge Connecting rod big end side clearance New measurement should be Step 5 Result B between 016 020 4 5 mm Clearance should Step 6 Result C not exceed 036 9mm Line B and Line C D Line D Line A End Play Polaris Industries Inc 3 15 5 98 ENGINE EC25PF EC28PF Engines Assembly Cont 10 Remove crankcase end seals and thoroughly clean the case half mating surfaces 11 Heat PTO side case half until it is hot to the touch 12 Reinstall crankshaft into heated case SERVE KINE _ TRW f 13 Heat mag side case half until it is hot to the touch 14 Place Loctite 518 gasket eliminator on one of the case halves 15 Reinstall the mag side half 16 Torque case half attaching bolts in
88. removal and crankcase separation Use caution while performing this proce dure Make sure that the puller is parallel to the shaft at all times Do not place side loads on the water pump shaft or strike the puller or shaft in any way 1 After the coolant has been drained remove the water ump cover impeller and the sealing washer Ill 1 Sealing Washer are i j oa Copper or Aluminum Sealing Washer Coolant Drain Bolt Impeller Mechanical Seal 2 Slide the main puller body over the outer portion of the mechanical seal as shown in Ill 2 and turn T Handle clockwise until it contacts water pump shaft Continue rotating until outer portion of mechanical seal is sepa rated from the metal seal body T Handle Main Puller Body Polaris Industries Inc 3 7 7a 5 98 ENGINE EH42PL EH50PL Engine Water Pump Mechanical Seal Removal Engine Installed Cont 3 Insert the puller legs between the water pump drive shaft and the remaining portion of the mechanical seal Attach the puller legs to the main puller body Ill 3 Puller Legs 4 Ensure that the split between the puller legs is fully sup ported by the main body of the tool Ill 4 Main puller 90 to opening on main puller 5 Tighten the hex socket screws on the puller legs suffi ciently so the lip of the puller legs will grasp the me chanical seal Ill 5 Lip must grasp inside of mechanical seal 6 Turn the puller T Handle clockwise until it contacts
89. s page 3 43 3 73 for reference Use the crankshaft installation tool kit PN 2871283 to prevent damage to the crankshaft and main bearings during installation 1 Install the crankshaft into the PTO side crankcase Screw the threaded rod into the crankshaft until the threads are engaged a minimum of one inch 25 4mm 2 Install the collar washer and nut onto the threaded rod Hold the crankshaft and tighten the nut to draw the crankshaft into the main bearings until fully seated Loosen the nut and remove the threaded rod from the crankshaft If removal is difficult install two nuts on the end of the threaded rod and tighten against each other 3 Install the proper shim on the magneto end of the crankshaft 4 Place the balancer shaft in the PTO crankcase aligning the timing marks on the crankshaft and balancer gears Install the proper shim washer on the shaft 5 Inspect the oil pump sealing surface on the crankcase Apply a light film of engine oil to the surface and install the oil pump NOTE Do not use gasket sealer on the pump mating surfaces 6 Align the drive gear with the drive pin on the pump shaft and install the gear Be sure the gear is fully seated and properly engaged 7 Install the proper shim washer on the pump shaft Crankcase Assembly 1 Apply 3 Bond 1215 P N 2871557 to the crankcase mating surfaces Be sure the alignment pins are in place 2 Set the crankcase in position carefully to avoid damaging
90. s cross pattern until loose 3 Remove bolts and tap cylinder head lightly with a plastic hammer until loose CAUTION Tap only in reinforced areas or on thick parts of cylinder head casting to avoid damaging casting 4 Remove cylinder head and head gasket Note the O Ring in the corner of the gasket which seals the front left cylinder stud The O Ring is part of the fiber type gasket NOTE This gasket has been superceded by an all metal gasket which does not require an O ring Cylinder Head Disassembly Inspection 1 Thoroughly clean cylinder head surface to remove all traces of gasket material and carbon CAUTION Use care not to damage sealing surface Polaris Industries Inc 3 51 5 98 ENGINE EH42PL EH50PL Engine Engine Disassembly Cont Cylinder Head Warpage 1 Lay a straight edge across the surface of the cylinder head at several different points and measure warpage by inserting a feeler gauge between the straight edge and the cylinder head surface If warpage exceeds the service limit replace the cylinder head Cylinder Head Disassembly WARNING Wear eye protection or a face shield during cylinder head disassembly and reassembly NOTE Keep all parts in order with respect to their location in the cylinder head 1 Using a valve spring compressor compress the valve spring and remove the split keeper NOTE To _ prevent loss of tension do not compress the valve spring more than necessary 2
91. stone contacts the cylinder walls CAUTION Do not overtighten Cylinder damage may result 4 With a 1 2 drill motor at a speed of 300 500 RPM run the hone in and out of the cylinder rapidly until cutting tension decreases Remember to keep the hone drive shaft centered and to bring the stone approximately 1 2 1 3 cm beyond the bore at the end of each stroke 5 Release the hone at regular intervals and inspect the bore to determine if it has been cleared and to check piston fit NOTE Don t allow cylinder to heat up during honing The thinner areas of the liner around the ports will expand causing uneven bore 6 After honing has been completed inspect all port Opening areas for rough or sharp edges Apply a slight chamfer to all ports to remove sharp edges or burrs paying particular attention to the corners of the intake and exhaust ports Polaris Industries Inc 3 33 10 96 ENGINE Piston Cylinder Clearance 2 Strokes Follow new engine break in procedures after replac ing piston rings Pre mix the first tank of fuel Bleed oil pump and warm engine thoroughly Avoid sus tained full throttle for the first two tanks of fuel Confirm oil system is working properly Oil level in reservoir should drop after first tank of fuel Cylinder Inspection Measurement Inspect cylinder for wear scratches or damage If no damage is evident measure cylinder for taper and out of round with a telescoping gauge and micrometer
92. the water pump shaft Continue rotating until the remaining portion of mechanical seal has been removed from the cases ll 6 Pump shaft oil seal can also be replaced at this time if necessary 7 Special tool PN 5131135 is required to install the new mechanical seal This tool is available separately and it is also included in the Crankshaft Water Pump Seal Installation Kit PN 2871283 5 98 7 3 77b Polaris Industries Inc ENGINE EH42PL EH50PL Engine Assembiy Cont One Way Valve Installation instali fhe one way valve plunger spring and plug us Ing a new sealing washer Cam Chain Drive Sprocket installation j Install the Woodruff key drive sprocket and slotted nut Tighten the nut to the specified torque Sear hats A bape n EA dg AML Meg eww Leip high VAAN ein eid RASUNA PPEP EEA EEA AERE E E EEEE EN E TELE AETAT EEEN E Tensioner Blade Installation 1 install the tensioner blade and tighten the mounting bolt to specified torque Piston Aing installation NOTE Apply clean engine oll to all ring surfaces and ring lands Always check piston ring installed gap before rings are installed on piston See page 3 65 If the piston has been In service clean any accumulated carbo from the ring grooves and oil control ring holes t Place the olf control ring expander in oil ring me with the end gap facing forward The expander has no us overlap 2 Install the oil ring top rall NOTE The to
93. the valve spring side of the cylinder head Ream each guide to size by turning the reamer clockwise continually Continue to rotate reamer clockwise during removal of the tool 9 Clean guides thoroughly with hot soapy water and anylon brush Rinse and dry with compressed air Apply clean engine oil to guides t Valve Seat Reconditioning Follow the manufacturers instructions provided with the valve seat cutters in the Cylinder Head Recondi tioning Kit PN 2200634 Abrasive stone seat re conditioning equipment can also be used Keep all valves in order with their respective seat NOTE Valve seat width and point of contact on the valve face is very important for proper sealing The valve must contact the valve seat over the entire cir cumference ofthe seat and the seat must be the prop Uneven Good er width all the way around Ifthe seat is uneven com pression leakage will result If the seat is too wide seat pressure is reduced causing carbon accumulation and possible compression loss If the seat is too nar row heat transfer from valve to seat is reduced and the valve may overheat and warp resulting in burnt valves 7 96 3 56 Polaris Industries Inc ENGINE EH42PL EH50PL Engine Engine Disassembly Cont Valve Seat Reconditioning 1 Install pilot into valve guide 2 Apply cutting oil to valve seat and cutter 3 Place 46 cutter on the pilot and make a light cut 4 Inspect the cut area of the seat e
94. the valves one at a time to maintain proper order 1 Install new valve seals on valve guides NOTE The intake and exhaust valve seals are different and must be installed on the proper guide 2 Apply engine oil to valve guides and seats 3 Coat valve stem with molybdenum disulfide grease 4 Install valve carefully with a rotating motion to avoid damaging valve seal 5 Dip valve spring and retainer in clean engine oil and install spring with closely spaced coils toward the cylinder head Closely spaced coils toward cylinder head 6 Place retainer on spring and install valve spring compressor Compress spring only enough to allow split keeper installation to prevent loss of spring tension Install split keepers with the gap even on both sides 7 Repeat procedure for remaining valves 8 When all valves are installed tap lightly with soft faced hammer on the end of the valves to seat the split keepers Polaris Industries Inc 3 59 7 96 ENGINE EH42PL EH50PL Engine Engine Disassembly Cont Vaive Sealing Test 1 Clean and dry the combustion chamber area 2 Pour a small amount of clean high flash point solvent into the intake port and check for leakage around each intake valve The valve seats should hold fluid with no seepage 3 Repeat for exhaust valves by pouring fluid into exhaust port Cylinder Piston Removal and Inspection Follow engine disassembly procedures to remove valve cover camshaft
95. ting to remove valve guides CAUTION Carbon deposits are extremely abrasive and may damage the valve guide bore when guides are removed 2 Place new valve guides in a freezer for at least 15 minutes while heating cylinder head 3 Heat cylinder head in an oven or use a hot plate to bring cylinder head temperature to 212 F 100 C CAUTION Do not use a torch to heat cylinder head or warpage may result from uneven heating Head temperature can be checked with a pyrometer or a welding temperature stick 4 When thoroughly heated place cylinder head on blocks of wood which will allow the old guides to be removed 5 Using valve guide driver drive guides out of the cylinder head from the combustion chamber side Be careful not to damage guide bore or valve seat when removing guides Polaris Industries Inc 3 55 7 96 ENGINE EH42PL EHS50PL Engine Engine Disassembly Cont 6 Place cylinder head on cylinder head table NOTE Be sure cylinder head is still at 212 F 100 C before installing new guides 7 Place a new guide in the valve guide installation tool and press guide in to proper depth Check height of each guide above the cylinder head NOTE The guide can be driven in to the proper depth Inspect the guide closely for cracks or damage if a driver is used 8 Allow cylinder head to cool to room temperature Apply cutting oil to the reamer supplied with the cylinder head service kit Guides should be reamed from
96. ts If cylinder is tapered or out of round beyond 002 the cylinder must be re bored oversize or replaced Piston to Cylinder Clearance 1 Measure piston outside diameter at a point 5 mm up from the bottom of the piston at a right angle to the direction of the piston pin 2 Subtract this measurement from the maximum cylinder measurement obtained in step 5 above Panasaran YY A ngynnganegnent at itil isiesn tesa a Std 3 4596 Polaris Industries Inc 3 63 5 98 ENGINE EH42PL EH50PL Engine Engine Disassembly Cont 3 Measure piston pin bore 4 Measure piston pin O D Replace piston and or piston pin if out of tolerance 5 Measure connecting rod small end ID 6 Measure piston ring to groove clearance by placing the ring in the ring land and measuring with a thickness gauge Replace piston and rings if ring to groove clearance exceeds service limits 7 96 3 64 Polaris Industries Inc ENGINE EH42PL EHS50PL Engine Engine Disassembly Cont Piston Ring Installed Gap 1 Place each piston ring inside cylinder using piston to push ring squarely into place 2 Measure installed gap with a feeler gauge at both the top and bottom of the cylinder NOTE A difference in end gap indicates cylinder taper The cylinder should be measured for excessive taper and out of round 3 Ifthe bottom installed gap measurement exceeds the service limit replace the rings NOTE Always check piston ri
97. tttt i PLE nesi ah ar eriiaseaney isabibelaagayartsnttttity Bae TEREE PENNIR AE HIA E E E n it BRE Saat Sh peni sindi PEREPERE AREER E add Rad sete nee esennage aneeetse Hessen ot eat A id BELO re a aariaid Cait i TETTEI RAREETETIREN no vane PENERIMAAN p Eea aee an EREET ITTE ITTI r wan sHBe TL ve ite TISrMRSAEESEEa TOT ENTITE Hee Bay E Heda un ao M Cn fee I cer ery tant handy Se ely nm diay ays m Han vite dun t Automatic Compression Release Installation Slide spring onto shaft 2 Apply engine oil to release lever shaft The actuator ball must be held outward to allow instal lation of the release lever shaft If Camshaft Is Removed From Engine 3 Turn the camshaft until the actuator ball is in the lowest position and install the release lever shaft pre winding the spring approximately 1 4 6 5mm If Camshaft Is Installed In The Engine Preload approx 1 4 6 5mm 4 Use a small magnet to draw the actuator ball outward or rotate the engine until the cam lobes face upward and install release lever shaft 5 Position camshaft as shown at bottom of illustration at right 6 Place arm of spring under stop pin as shown and push release lever inward until fully seated Do not pre wind the spring one full turn or the compression release will not disengage when the engine starts Check operation of mechanism as outlined in step 1 of Removal above NOTE When shaft is properly installe

9913680 1996-1998 Vol. II ATV Service Manual Chapter

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