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9915083 1999-2000 Vol. III ATV Service Manual Chapter

1. 3 48 EH50PL Engine Exploded View 3 49 ES33PF EH50PL Engine Removal 3 50 ES33PF EH50PL Engine Top End Disassembly 3 50 3 65 ES33PF EH50PL Valve Seat Service 3 66 3 71 ES33PF EH50PL Engine Bottom End Disassembly 3 72 3 89 ES33PF EH50PL Crankcase amp Bearing Assembly 3 90 ES33PF EH50PL Crankshaft End Play Inspection 3 91 3 92 ES33PF EH50PL Counter Balancer End Play Insp 3 93 3 94 ES33PF EH50PL Engine Assembly Inspection 3 95 3 109 Sealed Recoil Disassembly Inspection 3 110 3 111 Sealed Recoil Assembly 00 0 eee eee 3 112 Spark Plug Fouling Checklist 0 0 3 113 2 Stroke Troubleshooting 00ee eee eee 3 114 3 115 4 Stroke Troubleshooting 00ee ee eeee 3 116 3 118 ENGINE Torque Specifications 2 Cycle TORQUE SPECIFICATIONS 2 CYCLE ENGINES 250 300 400 EC25PFE EC 28PFE EC38PLE Ft Lbs Nm Ft Lbs Nm Ft Lbs Nm Cylinder Head Bolts 8mm 18 20 24 27 18 20 24 27 18 20 24 27 Cylinder Base Bolts 25 29 34 40 25 29 34 40 25 29 34 40 Crankcase 8mm 17 18 23 24 17 18 23 24 17 18 23 24 Crankcase 6mm 6 8 8 11 6 8 8 11 6 8 8 11 Crankshaft Slotted Nut fo oe 4 29 44 40 60 Water Pump Impeller Nut 6mm es 5 6 5 7 9 Stator Plate 6mm 5 6 5 7 9 5 6 5 7 9 5 6 5 7 9 Flywheel 44 62 60 85 44 62 60 85 29 44 40 60 Starter Motor 6mm 5 6 5
2. Polaris Sales Inc 37 4 99 ENGINE Service Data EH42PLE02 EH50PLE04 06 08 09 Engine Service Data Cylinder Piston Connecting Rod Cylinder 0020 05 mm 0020 05 mm 0020 050 mm Piston clearance Outer diameter 3 4596 3 4600 87 875 87 885 mm 3 6206 3 6210 91 96 91 97 mm Standard inner diameter of piston pin bore 9055 9057 23 0 23 006 mm Piston Pin Outer diameter 9053 9055 22 994 23 0 mm Standard clearance piston pin to pin bore 0002 0003 004 008 mm Degree of fit Piston pin must be a push by hand fit at 68 F 20 C Piston Ring Piston ring installed gap Top ring 0079 0138 20 36 mm 039 7 0 mm Second 0079 0138 20 36 mm ing 039 0 mm Oil ring 0079 0276 20 70 mm 059 1 5 mm Piston Ring Standard clearance Top ring 0016 0031 040 080 mm 0016 0031 040 080 mm piston ring to ring groove 0059 15 mm 0059 15 mm Second 0012 0028 030 070 mm 0012 0028 030 070 mm ring 0059 15 mm 0059 15 mm 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 ar 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
3. PN 2871460 4 99 3 108 Polaris Sales Inc ENGINE ES33PF EH50PL Engine Assembly Cont Rocker Shaft Rocker Arm Assembly Installation Assemble rocker arms rocker shaft and shaft supports Install and tighten rocker arm shaft locating bolt Apply molybdenum disulfide grease to the cam lobes and cam follower surfaces Rotate 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 Oak WN gt Rocker Shaft Support Tower Bolt Torque 9 ft Ibs 1 242 kg m Rocker Shaft Locating Bolt Torque 6 ft Ibs 828 kg m 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 Rocker Cover Bolt Torque 6 ft Ibs 828 kg m 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 Oil Pipe Bolt Torque 20 ft Ibs 2 76 kg m Polaris Sales Inc 3 109 4 99 ENGINE ES33PF EH50PL Engine Recoil Starter Recoil Disassembly
4. 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 Magneto end crankshaft main bearing After returning to the engine sump oil is drawn by the scavenge pump out of the sump and through a screen Scavenged oil is directed through another crankcase oil passage through the outlet hose to the thermo valve and directly back to the oil tank When the oil reaches a pre determined temperature the thermo valve opens to direct oil through the cooler and then back to the tank ES33 Oil Cooler Thermo Valve HOT COLD cooled af in from cooler Valve Valve Open i eee gt J cooled Hh ka out to oil tank AN L E ns oil n EE ca F l GEER GS Valve Cy j Closed aa E warm hot i hot e in from engine out to cooler ot in To engine E CT SS ad ee 4 99 Polaris Sales Inc Oil passes through cylinder head bolt passage to camshaft Thermo valve to cooler Cooler to thermo valve Oil bypasses Ng cooler at valve when cold gt Cooled Oil gt Hot Oil Path Bottom fitting is oil outlet or return to tank 335 ES33PFE Oil Flow Chart Top of Oil Tank Filtered Oil ENGINE Oil Flow Diagram ES33PF 335 ES33PFE Engine Also refer to thermo valve flow d
5. 1 Install the Woodruff key drive sprocket and slotted nut Tighten the nut to the specified torque Slotted Nut Torque 35 51 ft Ibs 4 71 6 86 kg m Tensioner Blade Installation 1 Install the tensioner blade and tighten the mounting bolt to specified torque Tensioner Blade Mounting Bolt Torque 6 ft Ibs 828 kg m 4 99 3 98 Polaris Sales Inc ENGINE EH50PL Engine Piston Ring Installation NOTE Apply clean engine oil to all ring surfaces and ring lands Always check piston ring installed gap before rings are installed on piston See page 3 74 If the piston has been in service clean any accumulated carbon from the ring grooves and oil control ring holes 1 Place the oil control ring expander in oil ring groove with the end gap facing forward The expander has no up or down marking and can be installed either way The ends should butt squarely together and must not overlap 2 Install the oil ring top rail NOTE The top rail has a locating tab to prevent rota tion The tab must be positioned in the notch on the side of the piston as shown A Polaris Sales Inc 3 99 4 99 ENGINE ES33PF EH50PL 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 4 Install the second ring with the R mark facing up Position the end gap toward the rear intake side of the piston 5 Ins
6. 101 2 mm Ex Valve Spring Free length Std 1 654 42 0 mm Limit 1 575 40 0 mm Squareness 075 1 9 mm 2 5 Margin thickness Valve Stem diameter lie al x lt Stem oil clearance x lt x lt E Qa Z 3 Polaris Sales Inc 3 5 4 99 ENGINE Service Data ES33PFEO1 02 Engine Service Data Cylinder Piston Connecting Rod ES33PFE0OL Cylinder 00207 05 mm 002 05 mm Piston clearance Outer diameter 3 0704 3 0720 77 93 77 97 mm Piston Pin Piston pin must be fitted into position with thumb at 68 F 20 C Piston Ring Piston ring installed gap Top ring Limi Oil ring S 0079 0276 20 70 mm Limi Piston Ring Standard clearance Top ring S piston ring to ring groove Limit Second ring 0059 15 mm Connecting Rod Connecting rod small end radial clear SR 0020 05 mm Connecting rod big end side clearance 0039 0256 1 65 mm Connecting rod big end radial clear ae 0020 05 mm Crankshaft Crankshaft runout limit 0024 06 mm KEY Std Standard OS Oversize ID Inner Diameter OD Outer Diameter Mag Magneto Side PTO Power Take Off Side Std Second Std td td ring Limit 039 1 0 mm 4 99 3 6 Polaris Sales Inc ENGINE Service Data EH42PLE02 EH50PLE04 06 08 09 Engine Service Data Rocker Am Rocker arm ID Rocker shaft OD 8656 8661 21 987 22 0 mm 8656 8661 21 987 22 0 mm Rocker shaft Oil Clear
7. 006 15 Sport 08 09 18 38 06 09 Scrambler 400 4 99 3 4 Polaris Sales Inc ENGINE Engine Specifications ES33PFEO1 02 Engine Service Data Cylinder Head Valve ES33PFE01 02 Rocker Arm Rocker arm ID 8669 8678 22 020 22 041 mm 1 Rocker shaft OD 8656 8661 21 987 22 0 mm Rocker shaft Oil Clearance Std 0008 0021 020 054 mm Limit 0039 10 mm Camshaft Cam lobe height Std 2884 1 2924 32 726 32 826 mm Limit 2766 32 426 mm Std 2884 1 2924 32 726 32 826 mm Limit 2766 32 426 mm Camshaft journal OD Mag 4935 1 4941 37 935 37 950 mm Peres PTO 4935 1 4941 37 935 37 950 mm Camshaft journal bore ID Mag 4963 1 4970 38 005 38 025 mm poet PTO 4963 1 4970 38 005 38 025 mm Camshaft Oil clearance Std 0022 0035 055 090 mm Ee x lt gt a afla Limit 0039 10 mm Cylinder Head Surface warpage limit 0020 05 mm Pore Standard height 3 870 98 3 mm 028 7 mm 055 1 4 mm 039 1 0 mm 071 1 8 mm Valve Seat Contacting width Valve Guide Inner diameter 2362 2367 6 0 6 012 mm Protrusion above head 689 709 17 5 18 0 mm Em x lt 039 1 0 mm 031 8 mm 047 1 2 mm 031 8 mm 2343 2348 5 950 5 965 mm 2341 2346 5 945 5 960 mm 0014 0024 035 062 mm 0016 0026 040 067 mm imi 0059 15 mm Overall length 3 976 101 0 mm 3 984
8. 0004 0015 011 038 mm eee 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 4 99 3 8 Polaris Sales Inc ENGINE Cooling System WARNING Never remove radiator cap when engine 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 Locate hole about 1 5mm diameter on inside of radiator below filler neck Radiator Hole must be clear to allow ease of bleeding the system Thermostat 4 Cycle Only Fan Switch Location Cylinder Cylinder _ Bleed Hole Inspection When coolant is added air is purged through a bleed hole at the top between the two halves see illustration above If there is difficulty bleeding the cooling system or if overheating problems are encountered remove the radiator cap and inspect to see if the bleed hole is clear tail T Vent hole inside cap liner must be clear System Pressure Test 1 Remove radiator cap access panel from front of headlamp housing 2 Remove recovery bottle hose from radiator 3 Connect a Mity Vac PN 2870975 to ee Press re tesi radiator and pressurize system to 10 PSI The a here with cap system must retain 10 lbs of pressure for five in place minutes or
9. Assembly Cont 7 Place the dowel pins in the crankcase and install a new cylinder base gasket Cylinder Installation 1 Position the piston support block PN 2870390 A beneath the piston skirt to support the piston during cylinder installation 2 Apply clean engine oil to the ring compressor Snap On PN RCL30 and install the compressor following manufacturers instructions CAUTION Make sure the oil control ring upper rail tab is positioned properly in the notch of the piston Verify all ring end gaps are correctly located 3 Apply clean engine oil liberally to the cylinder bore and tapered area of the sleeve Install the cylinder with a slight rocking motion until the rings are captive in the sleeve 4 Remove the ring compressor 5 Push the cylinder downward until fully seated on the base gasket ENGINE ES33PF EH50PL Engine Polaris Sales Inc 3 101 4 99 ENGINE ES33PF EH50PL Engine Assembly Cont 6 Apply a light film of oil to the threads and flange surface of the cylinder mounting bolts 7 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 8 Tighten the cylinder bolts in three steps in a criss cross pattern and torque to specifications 9 Install the two 6mm bolts Cylinder Bolt Torque 10mm 46
10. When thoroughly heated place cylinder head on blocks of wood which will allow the old guides to be removed 2 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 3 Place cylinder head on cylinder head table NOTE Be sure cylinder head is still at 212 F 100 C before installing new guides 4 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 A Refer to specifications on page 3 5 3 8 NOTE The guide can also be driven in to the proper depth Inspect the guide closely for cracks or damage if a driver is used Reaming The Valve Guide 5 Allow cylinder head to cool to room temperature Apply cutting oil to the reamer Guides should be reamed from 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 6 Clean guides thoroughly with hot soapy water and anylon brush Rinse and dry with compressed air Apply clean engine oil to guides y y Valve Guide Installed Height Polaris Sales Inc 3 67 4 99 ENGINE Valve Seat Reconditioning Valve Seat Reconditioning cont 1 Install pilot into valve guide 2 Apply cutting oil to valve seat and cutter 3 Place 46 cutter on the pi
11. rated from the metal seal body T Handle Main Puller Body 4 99 3 96 Polaris Sales Inc ENGINE 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 4 Ensure thatthe split between the puller legs is fully sup ported by the main body of the tool Ill 4 Main puller Position the split 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 the water pump shaft Continue rotating until the remaining portion of mechanical seal has been removed from the cases Ill 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 Polaris Sales Inc 3 97 4 99 ENGINE ES33PF EH50PL Engine Assembly Cont One Way Valve Installation Install the one way valve plunger spring and plug us ing a new sealing washer One Way Valve Plug Torque 16 ft Ibs 2 2 kg m Cam Chain Drive Sprocket Installation
12. tank Union Fitting Lower Oil Pump Scavenging Small End Bearing Cylinder Sleeve Main Bearing PTO Large End Bearing Indirect Lubrication E si Oil Jet Crankshaft Crankcase Oil Gallery Polaris Sales Inc 3 47 4 99 ENGINE ES33PFEngine Exploded View Crankcase Cylinder Cylinder Head Crankshaft Valve Train and Piston 4 99 3 48 Polaris Sales Inc ENGINE EHS50PL Engine Exploded View Crankcase Cylinder Cylinder Valve Train Polaris Sales Inc 3 49 4 99 ENGINE Engine Service ES33PF EH50PL Engine Removal Refer to page 3 11 3 13 for engine removal installation notes The following service procedures are for the ES33PF and EH50PL engines Difference are noted where neces sary Engine Disassembly Inspection Cam Chain Tensioner Rocker Arm Camshaft Removal 1 Remove ignition timing inspection plug from recoil housing To position crankshaft at Top Dead Center TDC on compression stroke 2 Rotate engine slowly in the direction of rotation L toc T Mark watching intake valves open and start to close 3 Continue to rotate engine slowly watching camshaft sprocket marks and the mark in the timing inspection hole Rotation gt Advance Marks 4 Align single TDC mark on flywheel with projection in inspection hole and the cam sprocket pin facing ES33PF upward aligned with the camshaft to
13. Crankcase 14mm 14 17 19 23 Nm 20mm __ 36 43 49 59 Nm 36 43 49 59 Nm 36 43 49 59 Nm 1 8 Pipe 6 5 11 9 15 Nm 6 5 11 9 15 Nm 6 5 11 9 15 Nm Thread 6mm 5 6 5 7 9 Nm 5 6 5 7 9 Nm 5 6 5 7 9 Nm mm 1 5 2 2 3 Nm 1 5 2 2 3 Nm 1 5 2 2 3 Nm 11mm 14 19 20 25 Nm 14 19 20 25 Nm 14 19 20 25 Nm 6mm 5 6 5 7 9 Nm 5 6 5 7 9 Nm 5 6 5 7 9 Nm 6mm 7 8 9 11 Nm 7 8 9 11 Nm 7 8 9 11 Nm 8mm 8 10 11 13 Nm 8 10 11 13 Nm 6mm 6 7 8 10 Nm 6 7 8 10 Nm 6 7 8 10 Nm 5 6 5 7 9 Nm 5 6 5 7 9 Nm 5 6 5 7 9 Nm 5 6 5 7 9 Nm mm 5 6 5 7 9 Nm 5 6 5 7 9 Nm 5 6 5 7 9 Nm 6mm 5 6 5 7 9 Nm 5 6 5 7 9 Nm 5 6 5 7 9 Nm 9 11 12 15 Nm 9 11 12 15 Nm 9 11 12 15 Nm 4 99 32 Polaris Sales Inc ENGINE Engine Fastener Torque Patterns Tighten cylinder head cylinder base and crankcase fasteners in 3 steps following the sequence outlined below aan G o Cylinder Head Cylinder Head Cylinder Base 250 300 400 250 300 400 Nee o 9 Og O O Cylinder Head Crankcase Crankcase Cylinder Base 400L 250 300 335 425 500 O Q 20 Crankcase 335 425 500 Polaris Sales Inc 3 3 4 99 ENGINE Piston Identification Piston Identification Note the directional and identification marks when viewing the pistons from the top The letter F i or must always be toward the flywheel side of the engine The othe
14. EXAMPLE OF CROSS HATCH PATTERN ing with fine grit stones to provide the proper cross hatch finish and required piston clearance A finished cylinder should have a cross hatch pattern to ensure piston ring seating and to aid in the retention of the fuel oil mixture during initial break in Hone cylinder according to hone manufacturer s instructions or these guidelines S Use a motor speed of approximately 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 or cylinder centered on arbor and to bring the stone approximately 1 2 1 3 cm beyond the bore at the end of each stroke S Release the hone at regular intervals and inspect the bore to determine if it has been cleared and to check piston fit NOTE Do not allow cylinder to heat up during honing The thinner areas of the liner around the ports will expand causing uneven bore S After honing has been completed inspect all port opening areas for rough or sharp edges Apply a slight cham fer to all ports to remove sharp edges or burrs paying particular attention to the corners of the intake and exhaust ports IMPORTANT Cleaning the Cylinder After Honing It is very important that the cylinder be thoroughly cleaned after honing to remove all grit material Wash the cylinder in a solvent then in hot soapy water Pay close attention to areas where the cylinder sleeve meets the aluminum casting
15. If 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 cavitate and cause overheating 6 The photo at right illustrates checking clearance measurement with a dial caliper A feeler gauge can also be used to check thickness by removing half of the putty or clay from the impeller blade Impeller 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 seal is identified by counting the number of sealing lips Itis a triple lip seal and has a protruding edge that faces away from the spring The oil seal is a double lip variety lt i The lip on the spring end angles ea back toward the spring The spring 4 a Counterbalance Lip Spring Lip Spring Toward Toward Impeller Counterbalance end of the seals open side must face the oil or coolant as shown in Closed Side Oil Seal Water Seal 3084184 3084185 the illustration Toward Each To assemble the pump casing Other press the bearing into the casing until flush with the casting Note Press Oil Seal Do not press the bearing in until it Past Weep Hole seats against the shoulder or the oil hole will be covered by the bear Oil Hole 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 i
16. 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 extended approximately 12 18 Check handle c ring for proper tension and the handle for cracks or damage which may allow water or dirt to enter the recoil housing through the rope NOTE The handle must seal tightly on the recoil housing to prevent water from entering 3 Remove center bolt from recoil friction plate A 4 Inspect plate for wear or damage Inspect plate friction spring for wear damage and proper tension The spring should fit tightly on friction plate 5 Remove ratchet pawl with spring and inspect Replace spring or ratchet pawl if worn broken or damaged NOTE Long arm of spring engages reel Short end against pawl 4 99 3 110 Polaris Sales Inc Recoil Disassembly Inspection Cont 6 7 10 11 Hold reel firmly in housing Pull rope handle until 12 18 of rope is exposed and hold reel in place Place rope in notch on outer edge of reel Release tension on hub and allow reel to unwind approximately 6 7 turns until spring tension is released Slowly and carefully remove reel from recoil housing making sure the spring remains in the housing Inspect the reel hub and bushing A for wear Unwind rope and inspect for cuts or abrasions I
17. Period 2 Cycle 2 Cycle Engine Break In Period is defined as the first 3 hours of engine operation or one full tank of fuel 1 2 Cycle Pre mix the first FULL tank of fuel at a 40 1 ratio with Polaris Premium 2 Cycle Lubricant 2 Fillthe oil tank with Polaris injection oil Never substitute or mix oil brands Serious engine damage can result 3 Bleed oil pump thoroughly Refer to Chapter 2 4 Verify proper oil usage from oil tank during the first tank of fuel Instruct operator to observe oil level in tank during the first tank of fuel If the level has not dropped repeat the oil pump bleeding procedure fill the tank with pre mix and investigate problem oil tank vent or supply line restriction pump problem etc 5 Avoid prolonged idle heavy loads or periods of sustained full throttle Use low gear if available Vary throttle settings during the break in period Engine Break In Period 4 Cycle 4 Cycle Engine Break In Period is defined as the first 10 hours of engine operation or 2 full tanks of fuel 1 Use only Polaris Premium 4 All Season synthetic oil or API certified SH oil Never substitute or mix oil brands Serious engine damage can result 2 Use fuel with a minimum octane of 87 R M 2 method 3 Change break in oil and filter at 20 hours or 500 miles whichever comes first Polaris Sales Inc 3 13 4 99 ENGINE EC25PF EC28PF Engine Disassembly NOTE Inspect all parts during disassembly as outline
18. Sales Inc 3 41 4 99 ENGINE Notes 4 99 3 42 Polaris Sales Inc ENGINE Lubrication Engine Lubrication ES33PF EH50PL Oil Type 22 0000 Polaris Premium 4 Synthetic PN 2871281 or API certified SH 5W30 oil Capacity 085 Approximately 2 U S Quarts 1 9 1 Piller EPEE EE E PN 3084963 Filter Wrench Snap On PN YA997 or equivalent Drain Plug Screen Fitting 14 ft Ibs 19 Nm Oil Pressure Specification 20 PSI 5500 RPM Polaris OW 40 Synthetic Engine Hot Oil Pressure Test ES33PF EH50PL 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 NOTE Use Polaris Premium 4 Synthetic Engine Lubricant Oil Pressure at 5500 RPM Engine Hot Standard 20 PSI Minimum 12 PSI Polaris Sales Inc 3 43 4 99 ENGINE Lubrication Oil Flow ES33PF Oil Flow ES33PF The ES33PF engine is equipped with a thermostatically controlled valve that directs oil returning to the tank through a cooler when the oil is hot Valve operation is described below The chart on page 3 44 describes the flow of oil through the ES33PF engine and oil cooler 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 th
19. both sides Repeat procedure for remaining valve When all valves are installed tap lightly with soft faced hammer on the end of the valves to seat the split keepers Valve Sealing Test 1 Clean and dry the combustion chamber area 2 Pourasmall 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 ENGINE Valve Seat Reconditioning Closely spaced coils toward cylinder head i lt y 3 Repeat for exhaust valves by pouring fluid into exhaust port Polaris Sales Inc 3 71 4 99 ENGINE ES33PF EH50PL Engine Engine Bottom End Disassembly Cylinder Piston Removal and Inspection Follow engine disassembly procedures to remove valve cover camshaft 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 EHS50PL 3 Loosen hose clamps and remove coolant inlet hose 4 99 3 72 Polaris Sales Inc ENGINE ES33PF EH50PL Engine Engine Disassembly Cont 4 Remove the two 6 mm cylinder base bolts ES33PF 5 Loosen each of the four large cylinder base bolts 1 4 turn at a time in a criss cross pattern until loose and remove bolts EHS50PL The bolts are inside the water jacket 6 Tap cylinder lightly with a plastic hammer in the r
20. crankshaft center line NOTE The cam lobe should be pointing down and valves should have clearance at this point 5 Remove cam chain tensioner plug sealing washer and spring CAUTION The plug is under spring tension Maintain inward pressure while removing 6 Remove the two 6x25 mm cam chain tensioner flange bolts 7 Tap lightly on tensioner body with a soft face hammer and remove tensioner 4 99 3 50 Polaris Sales Inc ENGINE ES33PF EH50PL Engine Engine Disassembly Cont Cam Chain Tensioner Inspection 1 Pull cam chain tensioner plunger outward to the end of its travel Inspect teeth on ratchet pawl A and plunger teeth B for wear or damage 2 Push ratchet pawl and hold it The plunger should move smoothly in and out of the tensioner body 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 Compare to specifications on page 3 5 3 8 5 Replace entire tensioner assembly if any part is worn or damaged Polaris Sales Inc 3 51 4 99 ENGINE ES33PF EH50PL Engine Rocker Arm Shaft Removal ES33PF 1 Slide shaft out of support boss keeping rocker arms in order Note position of spring washer on rocker shaft Flats face out toward the shaft support 1 Loosen rocker shaft retaining bolt A to remove shaft 2 Remove the four bolts securing rocker
21. 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 located in the stator plate 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 orifice 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 Magneto end crankshaft main bearing The one way valve is located on the front
22. gap exceeds the service limit Refer to page 3 4 for specifications Piston Ring NOTE Always check piston ring installed gap after re boring a cylinder or when installing new rings NOTE Install rings with mark facing UP Mark Faces Up Polaris Sales Inc 3 37 4 99 ENGINE Cylinder Hone Selection Honing 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 hone or arbor honing machine which also has the capability of oversizing 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 pattern in the bore CAUTION Honing To Oversize If cylinder wear or damage is excessive it will be nec essary to oversize the cylinder using a new oversize piston and rings This may be accomplished by either boring the cylinder and then finish honing to the final bore size or by rough honing followed by finish honing For oversize honing always wet hone using honing oil and a coarse roughing stone Measure the piston see piston measurement and rough hone to the size of the piston Always leave 002 003 05 07 mm for fin a ish honing Refer to piston to cylinder clearance spec ifications on page 3 4 before honing Complete the siz
23. is fully seated in the housing 6 Apply downward pressure on the reel and rotate counterclockwise approximately 6 7 turns to pre wind the spring Continue rotating counterclockwise until rope on outer edge aligns with rope guide bushing 7 Release rope from notch and allow reel to rewind Open end here completely If more pre wind is required place rope in S i notch and add additional turns of pre wind 8 Install ratchet pawl and return spring with long leg of spring engaged in reel 9 Reinstall friction plate NOTE The friction plate must be positioned with both end tabs of the friction spring opposite the ratchet pawl 10 Torque friction plate retaining bolt to 5 6 ft Ibs 7 9 Nm 11 Reinstall recoil housing using a new gasket Seal stator wire harness grommet with RTV silicone 4 99 3 112 Polaris Sales Inc ENGINE Spark Plug Fouling Checklist Spark Plug Fouling 2 Stroke Engines Wn NNnNNnNNNNNHNNNUHnNUHNNUnNNKnNNnNVnNDUHNNHnNNUnNVnNWN WH 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 wor
24. 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 4 99 3 114 Polaris Sales Inc ENGINE Piston Damage Troubleshooting 2 Stroke Engines Some items may not apply to all engines S Oil tank empty oil wrong type or contaminated S Oil filter restricted S Oil pump inoperative drive gear cable pump oil check valve restricted or faulty S 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 Wn 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 Cooling system cooling fins radiator fins restricted air flow obstructed Incorrect piston to cylinder clearance Air leaks in intake tract air intake ducts mounting flange damaged or loose Foreign material ingestion Air in oil pump lines Air in cooling system low coolant level Poor fuel quality Restricted exhaust Incorrect ignition timing Spark plug heat range incorrect Fan blade incorrectly installed or damaged Nnnnnnnnnnn Nn WN Air box carburetor or exhaust modified Polaris Sales Inc 3 115 4 99 ENG
25. or excessive axial or radial movement If play or roughness is evident with a new pin and bearing replace the connecting rod Piston Pin Measurement Locations Polaris Sales Inc 3 39 4 99 ENGINE Crankshaft Runout Inspection Crankshaft Straightening Lubricate the bearings and clamp the crankshaft securely in the holding fixture Refer to the illustrations below Crankshaft Alignment Fixture PN 2870569 NOTE The rod pin position in relation to the dial indicator position tells you what action is required to straighten the shaft 8 To correct a situation like the one shown in the illustration at right strike the shaft at point A with a PIGH004 ty brass hammer AlA HIGH 1 14mm ss SUPPORT CRANKSHAFT 9 To correct a situation like the one shown in the illustration at right squeeze the crankshaft at HIGH 002 05mm point A Use tool from alignment kit HIGH 005 13mm A 10 If the crank rod pin location is 180_ from the dial indicator opposite that shown above it will be necessary to spread the crankshaft at position A as shown in the illustration at right When rebuilding and straightening a crankshaft runout must be as close to zero as possible HIGH 002 05mm A A HIGH 005 13mm NOTE Maximum allowable runout is 0041 1 mm for 2 stroke engines and 0024 for 4 stroke engines 4 99 3 40 Polaris Sales Inc ENGINE 4 Stroke Engine Service Polaris
26. pump to return to idle position Water pump gasket Water pump seal Add fuel as required Clean line replace filter Clean or replace valve as necessary 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 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
27. transfer port area Use electrical contact cleaner if necessary to clean these areas Rinse thoroughly dry with compressed air and oil the bore immediately with Polaris 2 Cycle Lubricant 4 99 3 38 Polaris Sales Inc ENGINE Connecting Rod Small End Inspection 2 Stroke Engines Connecting Rod Small End Bearing 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 Feel the bearing surface inside the rod and check for CN rough spots galling or wear 3 Clean needle bearing in solvent and dry with compressed air 4 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 5 Visually inspect piston pin for damage discoloration or wear Feel along the length of the pin and replace it if any rough spots galling or wear is detected 6 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 back and forth through bearing while rotating and check for rough spots 7 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
28. 518 on both sides of the base gasket Oil check valve should release as specified below 4 Reinstall stat lat d alian timi k Stator Plate Timing einstall stator plate and align timing marks Advance Retard Refer to Electrical Chapter 10 for dynamic ignition Center the mark 3 timing with stator plate attaching screw hol 2 Reinstall flywheel All models 3 Reinstall magneto housing 4 Torque flywheel bolt to specification found on page 3 1 5 Reinstall recoil starter assembly 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 4 99 3 20 Polaris Sales Inc 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
29. 7 9 5 6 5 7 9 5 6 5 7 9 Recoil Housing 6mm 5 6 5 7 9 5 6 5 7 9 5 6 5 7 9 Spark Plug New 9 11 12 15 9 11 12 15 9 11 12 15 Spark Plug Used 17 20 23 27 17 20 23 27 17 20 23 27 Drive Clutch Bolt 40 55 40 55 40 55 Polaris Sales Inc 3 1 4 99 ENGINE Torque Specifications 4 Cycle TORQUE SPECIFICATIONS 4CYCLE ENGINES 335 425 500 ES33PFE EH42PLE EH50PLE Ft Lbs Nm Ft Lbs Nm Ft Lbs Nm Blind Plug Oil Pressure 1 8 Pipe 6 5 11 9 15 Nm 6 5 11 9 15 Nm 6 5 11 9 15 Nm Thread Camshaft Sprocket 6mm 5 6 5 7 9 Nm 5 6 5 7 9 Nm 5 6 5 7 9 Nm Camshaft Chain Tensioner Lever 6mm 5 6 5 7 9 Nm 5 6 5 7 9 Nm 5 6 5 7 9 Nm Camshaft Chain Tensioner 6mm 5 6 5 7 9 Nm 5 6 5 7 9 Nm 5 6 5 7 9 Nm Camshaft Chain Tensioner Cap 11mm 14 19 20 25 Nm 14 19 20 25 Nm 14 19 20 25 Nm Carburetor Adaptor 8mm 12 14 16 20 Nm 12 14 16 20 Nm 12 14 16 20 Nm Crankcase 8mm 14 15 19 21 Nm 14 15 19 21 Nm 14 15 19 21 Nm Crankshaft Slotted Nut Cam 28mm 35 51 47 69 Nm 35 51 47 69 Nm 35 51 47 69 Nm Chain Drive Sprocket Cylinder Base Bolts 10mm 45 49 61 67 Nm 45 49 61 67 Nm 45 49 61 67 Nm 6mm 6 8 9 11 Nm 6 8 9 11 Nm 6 8 9 11 Nm Cylinder Head Bolts 11mm 47 nie 64 72 Nm Refer to Engine Assembly for torque 6mm aie 9 Nm 2a Drive Clutch Bolt 7 16 20 40 55 Nm Flywheel 16mm 58 72 78 98 Nm Oil Delivery Pipe 12mm 11 15 15 21 Nm Oil Drain Bolt
30. Bushing Clearance Std 0015 004 038 102 mm Service Limit 008 203 mm ENGINE ES33PF EH50PL Engine Polaris Sales Inc 3 79 4 99 ENGINE ES33PF EH50PL Engine Engine Disassembly Cont 6 Inspect gear teeth on starter drive Replace starter drive if gear teeth are cracked worn or broken 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 on stator plate 5 Replace crankshaft seal 6 Remove oil passage O Ring 7 Remove large sealing O Ring from outer edge of stator plate 4 99 3 80 Polaris Sales Inc ENGINE ES33PF EH50PL Engine Cam Chain Tensioner Blade 1 Remove bolt securing tensioner blade to crankcase A 2 Remove blade and inspect for cracks wear or damage 3 Remove cam 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 limit Chain Service Limit 5 407 13 7 cm Polaris Sales Inc 3 81 4 99 ENGINE ES33PF EH50PL Engine Engine Disassemb
31. CHAPTER 3 ENGINE Torque Specifications 2 Stroke 3 1 Torque Specifications 4 Stroke 3 2 Torque Patterns 0 eee 3 3 Piston Identification 00 cece eee ee 3 4 Piston Clearance Specifications 2 Stroke 3 4 ES33PF EH50PL Service Data 3 5 3 8 Cooling System Pressure Test 4 3 9 Cooling System Specifications 3 10 Engine Removal ii ens add pes of eee nee tee ees 3 11 3 12 Engine Installation Notes 00 eee 3 13 EC25PF EC28PF Engine Disassembly 3 14 3 15 EC25PF EC28PF Engine Assembly 3 16 3 20 EC25PF EC28PF Oil Pump End Play Adjustment 3 21 EC25PF EC28PF Oil Check Valve Testing 3 22 EC25PF Recoil Disassembly 0 3 23 EC25PF Recoil Assembly cccccke ceteerreceaion es 3 24 3 25 EC38PL Engine Disassembly 4 3 26 3 32 EC38PL Engine Inspection 2 0 eos cee ee ea es 3 32 3 35 Cylinder Piston Inspection 2 Stroke 3 36 3 37 Cylinder Honing 0 00 e eee eee eee 3 38 Connecting Rod Inspection 2 Stroke 3 39 Crankshaft Runout Inspection 2 Stroke 3 40 ES33PF EH50PL Engine Lubrication 3 43 ES33PF Lubrication Oil Flow 05 3 44 3 45 ES50PL Lubrication Oil Flow 05 3 46 3 47 ES33PF Engine Exploded View
32. INE 4 Stroke Troubleshooting Engine Turns Over But Fails to Start S NNnNNnNnNnNNN S No fuel Dirt in fuel line or filter Fuel will not pass through fuel valve Fuel pump inoperative restricted Tank vent plugged Carb starter circuit Engine flooded Low compression high cylinder leakage No spark Spark plug fouled Engine Does Not Turn Over S S S Dead battery Starter motor does not turn Engine seized rusted or mechanical failure Engine Runs But Will Not Idle Restricted carburetor pilot system Carburetor misadjusted Choke not adjusted properly Low compression Crankcase breather restricted Engine Idles But Will Not Rev Up NNnNNnNnNnNnNnNnNNN Wn Spark plug fouled weak spark Broken throttle cable Obstruction in air intake Air box removed reinstall all intake components Incorrect or restricted carburetor jetting ETC switch limiting speed Reverse speed limiter limiting speed Carburetor vacuum slide sticking diaphragm damaged Incorrect ignition timing Restricted exhaust system Engine Has Low Power S NNN WN S Spark plug fouled Cylinder piston ring or valve wear or damage check compression PVT not operating properly Restricted exhaust muffler Carburetor vacuum slide sticking diaphragm damaged Dirty carburetor Piston Failure Scoring S Lack of lubrication S Dirt entering engine through cracks in air filter or ducts S Engine oil dirty or contaminated 4 99 3 116
33. On 2 Strokes i 4 205 F 96 C 205 F 96 C System Capacity Po 225 Quarts O 2 25 sao 2 25 sao Radiator Cap Relief 13 PSI 13 ae R Pressure 4 99 3 10 Polaris Sales Inc ENGINE Engine Removal Accessible Components All Models The following components can be serviced or removed with the engine installed in the frame Wn NnNnnnnnnnnn Nn WN Flywheel Alternator Stator Starter Motor Starter Drive Cylinder Head Cylinder Piston RIngs Oil pump 250 400 Counterbalance Shaft or Bearing s 400 engines Camshaft 4 Strokes Rocker Arms Cam Chain and Sprockets 4 Strokes Water Pump Water Pump Mechanical Seal The following components require engine removal for service nNnnnn WN Oil pump Oil Pump Drive Gear 300 335 425 500 Counterbalance Shaft or Bearing s 4 Cycle engines Connecting Rod Crankshaft Crankshaft Main Bearings Crankcase It may be necessary to loosen engine mounts and move engine slightly to access water pump on some 4 stroke models Special tool PN 2872105 is required to replace mechanical seal with engine in frame Polaris Sales Inc 3 11 4 99 ENGINE Engine Removal Engine Removal Typical 1 2 3 4 20 21 Clean work area Thoroughly clean the ATV engine and chassis Disconnect battery negative cable Remove the following parts as required depending on model S Seat S Left and Right Side Covers Gen II and Gen IV Refe
34. Polaris Sales Inc ENGINE 4 Stroke Troubleshooting Excessive Smoke and Carbon Buildup S Excessive piston to cylinder clearance Wet sumping Worn rings piston or cylinder Worn valve guides or seals Restricted breather nnn Wn WN Air filter dirty or contaminated Low Compression S Decompressor stuck S 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 nnn nn WN Valve not seating properly bent or carbon accumulated on sealing surface S Rocker arm sticking Backfiring S ETC or speed limiter system malfunction S Fouled spark plug or incorrect plug or plug gap S Carburetion faulty lean condition S Exhaust system air leaks S 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 nnn Wn WN Lean condition Polaris Sales Inc 3 117 4 99 ENGINE 4 Stroke Troubleshooting EH42PL EH50PL Cooling System Troubleshooting Overheating S nn Wn WN nn nnnn nnn Wn WN Low coolant level Air in cooling system Wrong type of coolant Faulty pressure cap or system leaks Restricted system mud or debris in radiator fins or restriction to air flow passages blocked in r
35. Rotor Tip Clearance Std 005 127 mm Wear Limit 008 2032 mm 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 Oil Pump Assembly 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 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 Oil Pump Attaching Bolt Torque 6 ft Ibs 828 kg m 4 99 3 86 Polaris Sales Inc ENGINE ES33PF EH50PL Engine Engine Disassembly Cont 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 Turn the shaft until balancer counter weights clear the crankshaft and remove the balancer shaft from the crankcase 4 Inspect the balancer drive gear and pump shaft drive gear 5 Replace the shaft if gear teeth are abnormal
36. adiator lines pump or water jacket 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 or turning too slowly perform current draw test Ignition timing misadjusted Low oil level Spark plug incorrect heat range Faulty hot light circuit Thermostat stuck closed or not opening completely Temperature Too Low S Thermostat stuck open Leak at Water Pump Weep Hole S Faulty water pump mechanical seal coolant leak S Faulty pump shaft oil seal oil leak 4 99 3 118 Polaris Sales Inc
37. aft End Play 008 016 02 04 cm Pump Shaft Oil Seal Installation 1 Install the seal from the outside of the crankcase water pump side with the spring facing inward toward the pump shaft bearing 2 Drive or press the seal into place using a 25mm 985 seal driver until flush with the bottom of the mechanical seal bore 3 Lubricate the seal lip with grease 4 99 3 94 Polaris Sales Inc ENGINE ES33PF EH50PL Engine Assembly Cont Crankshaft Counter Balancer and Oil Pump Installation Lubricate all bearings with clean engine oil before assembly See engine disassembly photos page 3 50 3 89 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 Insta
38. ance Std Limit 0039 10 mm Std Limit 2884 1 2924 32 726 32 826 mm 2766 82426 mm Std 2884 1 2924 32 726 32 826 mm Limit 2766 32 426 mm Camshaft Cam lobe height Camshaft journal OD Mag 4935 1 4941 37 935 37 950 mm Peres PTO 4935 1 4941 37 935 37 950 mm 1 4935 1 4941 37 935 37 950 mm Camshaft journal bore ID Mag 4963 1 4970 38 005 38 025 mm poet PTO 4963 1 4970 38 005 38 025 mm Camshaft Oil clearance Std 0022 0035 055 090 mm Limit 0039 10 mm Cylinder Head Surface warpage limit 0020 05 mm Pore Standard height 3 870 98 3 mm 028 Tm 055 14 mm 39 TO mm OTT 1 8 mm Ee x lt gt a afla Valve Seat Contacting width Valve Guide Inner diameter 2362 2367 6 0 6 012 mm 2362 2367 6 0 6 012 mm Protrusion above head 689 709 17 5 18 0 mm 689 709 17 5 18 0 mm Em x lt 039 1 0 mm 03T 8 mm O47 1 2 mm 031 8 mm 031 8 mm 2343 2348 5 950 5 965 mm 2341 2346 5 945 5 960 mm 2341 2346 5 945 5 960 mm 0014 0024 035 062 mm 0014 0024 035 062 mm 0016 0026 040 067 mm im 00597 15 mm 976 104 0 mm 984 104 2 mm Overall length ete Valve Spring Overall length Std 654 42 0 mm Margin thickness Valve Stem diameter lie al x lt x lt x lt Stem oil clearance E Qa Z 3 w l Squareness 075 1 9 mm 075 1 9 mm
39. asure 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 Compare to specifications on page 3 5 3 8 NOTE If valve guides are replaced valve seats must be reconditioned Refer to Valve Seat Reconditioning for pro cedure Combustion Chamber Clean all accumulated carbon deposits from combustion chamber and valve seat area with a soft wire brush Polaris Sales Inc 3 65 4 99 ENGINE Valve Seat Reconditioning 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 67 If 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 befor
40. awl bracket in the corner of the jaws of a vise Clamp in 5 Using a cloth belt type strap wrench wrapped jise around the outside edge of the reel unscrew the reel counterclockwise to remove it from the ratchet pawl bracket shaft here Use vise 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 Pawl Guide 10 Friction Spring 11 Ratchet Pawl Bracket 12 Reel Housing 13 Pawl Return Spring 14 Recoil Rope 15 Rope Handle 16 Recoil Cup 17 Timing Plug 18 Bushing OANOARWN gt Polaris Sales Inc 3 23 4 99 ENGINE EC25PF Engine Recoil Assembly 1 If the recoil spring was removed reinstall it in its recess in the flywheel housing The spring should spiral counterclockwise toward the center Grease spring with Polaris low temperature grease Install recoil spring retaining plate Grease and install spring hook making sure it properly engages the spring end Install ratchet friction ring and friction spring assembly The friction spring should engage the bent tab on the recoil spring retaining plate The L on the friction ring should be positio
41. balancer shaft at the bearing seats with a dial caliper or micrometer and record reading 3 Measure the distance from the Mag crankcase mating surface to the balance shaft bearing using a dial caliper and a straight edge Subtract the thickness of the straightedge and record 4 Measure the distance from the PTO crankcase mating surface to the bearing using the same method outlined in Step 1 2 and 3 5 Add the readings obtained in Step 3 and Step 4 6 Subtract the counter balancer shaft width measured in step 2 from the figure obtained in step 5 Counter Balancer Shaft End Play 7 Subtract the thickness of the existing shim from 008 016 02 04 cm the result of step 6 to determine if a different shim coz open is needed The result must be within the specified range listed below Polaris Sales Inc 3 93 4 99 ENGINE ES33PF EH50PL Engine Assembly Cont Pump Shaft 1 Make sure the pump shaft bearing is firmly seated in the Magneto side crankcase 2 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 3 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 4 Subtract the thickness of the existing shim from the result of Step 3 to determine if a different shim is needed Pump Sh
42. cts the margin area B it is too high on the valve face Use the 30 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 face measure seat width If the seat is too wide or uneven use both top and bottom cutters to narrow the seat If the seat is too narrow widen using the 45 cutter and re check contact point on the valve face and seat width after each cut NOTE When using an interference angle the seat contact point on the valve will be very narrow and is a normal condition Look for an even and continuous contact point on the black marker all the way around the valve face ES33PF EH50PL Valve Seat Width Refer to Engine Service Specifications on Page 3 5 3 8 8 Clean all filings from the area with hot soapy water rinse and dry with compressed air 9 Lubricate the valve guides with clean engine oil and apply oil or water based lapping compound to the face of the valve Lapping is not required with an interference angle ENGINE Valve Seat Reconditioning po B i A Proper Seat Contact On Valve Face 4 Seat Width Bottom 60 or 75 Seat 45 or 46 Top amp 30 Polaris Sales Inc 3 69 4 99 ENGINE Valve Seat Reconditioning Valve Seat Reconditioning cont 10 11 12 13 14 Insert the valve into its respective guide and lap using a lapping
43. d carbon CAUTION Use care not to damage sealing surface ENGINE ES33PF EH50PL Engine Polaris Sales Inc 3 61 4 99 ENGINE ES33PF EH50PL Engine Engine Disassembly Cont Cylinder Head Warpage 1 Layastraight 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 Warpage Limit 002 05 mm 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 The EH50 cylinder head is shown in examples throughout cylinder head service section The ES33 cylinder head is similar to EH50 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 Remove spring retainer and spring NOTE The valve springs should be positioned with the tightly wound coils against the cylinder head on progres sively wound springs A 3 Push valve out keeping it in order for reassembly in the same guide 4 99 3 62 Polaris Sales Inc Engine Disassembly Cont 4 Measure free length of spring with a Vernier caliper Check spring for squareness Com
44. d on page 3 35 3 40 1 Remove the flywheel nut and flywheel with puller PN 2871043 Mark position of stator plate on crankcase Mark stator plate remove stator plate screws and stator assembly and crankcase d Flywheel Puller PN 2871043 Flywheel Holder PN 8700229 2 Remove cylinder head and cylinder Remove piston pin clips Use Piston Pin Puller to remove piston pin from piston 3 Refer to Top End Component Parts Inspection on page 3 36 3 39 to inspect cylinder piston rings and connecting rod small end bearing Piston Pin Puller PN 2870386 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 the crankshaft runout as outlined in Crankshaft Inspection procedure on page 3 40 4 99 3 14 Polaris Sales Inc Disassembly cont Connecting Rod Side Clearance 1 Measure clearance between lower rod and counterweight with a feeler gauge connecting rod big end side clearance New measurement should be between 016 020 4 5 mm Clearance should not exceed 036 9mm Crankshaft Main Bearing Inspection 1 Clean crankshaft thoroughly and oil main and connecting rod bearings with Polaris Premium 2 engine oil Carefully check each main bearing on the shaft NOTE Due to ex
45. e CAUTION Do not strike the oil pump shaft at an angle or the shaft may bend causing irreparable damage Tap only lightly on the pump shaft if necessary 4 Remove the Mag RH crankcase from the PTO case ENGINE ES33PF EH50PL Engine Polaris Sales Inc 3 83 4 99 ENGINE ES33PF EH50PL Engine Engine Disassembly Cont Oil Pump Removal Inspection 1 Remove pump shaft bearing A and thrust washer B from pump shaft 2 Remove pump drive gear C 3 Inspect drive gear teeth for cracks damage or excessive wear 4 Remove three oil pump retaining bolts and pump 5 Inspect mating surface of crankcase and oil pump Check for nicks burrs or surface irregularities 4 99 3 84 Polaris Sales Inc Engine Disassembly Cont 6 Remove the three screws and strainer screen from pump 7 Clean screen thoroughly 8 Remove pump body screw and feed chamber cover 9 Measure pump end clearance using a feeler gauge and straight edge Pump End Clearance Std 001 003 0254 0762 mm Wear Limit 004 1016 mm ENGINE ES33PF EH50PL Engine Polaris Sales Inc 3 85 4 99 ENGINE ES33PF EH50PL Engine Engine Disassembly Cont 10 Measure clearance between outer feed rotor and pump body with a feeler gauge Outer Feed Rotor to Pump Body Clearance Std 001 003 0254 0762 mm Wear Limit 004 1016 mm 11 Measure rotor tip clearance with a feeler gauge
46. e attempting 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 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 99 3 66 Polaris Sales Inc 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 of the seat and the seat must be the prop 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 ENGINE Valve Seat Reconditioning OOOO Too Uneven Good Too Wide Narrow 1
47. ealer 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 a fF wo N Remove the guide adaptor using the additional nut as a jam nut if necessary Water Pump Mechanical Seal Removal Engine Installed E H50PL 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 EH50PL engines without removing the engine and splitting the cases CAUTION y Improper or careless use of this tool or procedure can result in a bent water pump shaft Pump shaft replacement requires engine 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 pump cover impeller and the sealing washer Ill 1 Sealing Washer 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
48. easurement exceeds the service limit replace the rings NOTE Always check piston ring installed gap after re Cylinder i 25 50mm 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 Feeler Gauge Piston Ring Piston Ring Installed Gap Top Ring Second Ring Oil Ring Refer to Specifications on Page 3 5 3 8 4 99 3 78 Polaris Sales Inc Engine Disassembly Cont Crankcase Disassembly NOTE The recoil starter starter motor starter drive flywheel stator cam chain and sprockets can be serv iced with the engine in the frame 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 of the starter drive shaft on both ends and record 5 Measure the ID of the bushing in the recoil housing A 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 Std Bushing ID 4735 4740 11 11 12 04 mm Std Shaft OD 470 472 11 93 11 99 mm Starter Drive
49. einforced areas only until loose 7 Rock cylinder forward and backward and lift it from the crankcase supporting piston and connecting rod Support piston with piston support block PN 2870390 8 Remove dowel pins from crankcase Polaris Sales Inc 3 73 4 99 ENGINE ES33PF EH50PL Engine Engine Disassembly Cont Piston Removal ES33PF 1 Remove circlip Note piston orientation with circlip removal notch facing the front or rear The ES33 piston is non directional A new piston can be installed with the circlip notch facing either way However if a used piston is re installed install in the same direction as removed EHS50PL 1 Remove circlip Note piston directional arrow pointing toward the right Mag side of engine 2 Remove piston circlip and push piston pin out of piston If necessary heat the crown of the piston slightly with a propane torch CAUTION Do not apply heat to the piston rings The ring may lose radial tension 3 Remove top compression ring 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 EHS50PL The oil control ring is a three piece design consisting of a top and bottom steel ra
50. emoved components using new gaskets seals and fasteners where applicable 2 Perform regular checks on fluid levels controls and all important areas on the vehicle as outlined in the daily pre ride inspection checklist refer to Chapter 2 or the Owner s Safety and Maintenance Manual PVT System 1 Adjust center distance of drive and driven clutch Chapter 6 2 Adjust clutch offset alignment and belt deflection Chapter 6 3 Cleanclutch sheaves thoroughly and inspect inlet and outlet ducts for proper routing and sealing Chapter 6 Transmission 1 Inspect transmission operation and adjust linkage if necessary Refer to Chapter 2 and Chapter 8 Exhaust 1 Replace exhaust gaskets Seal connections with high temp silicone sealant 2 Check to be sure all springs are in good condition Bleed Cooling System Remove radiator cap and slowly add coolant to top of filler neck Fill coolant reservoir tank to full mark Loosen bleed screw at top of cylinder head 400 until all air is purged from engine Tighten bleed screw Install radiator cap and squeeze coolant lines to force air out of system Again remove radiator cap and slowly add coolant to top of fill neck Start engine and observe coolant level in the 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 necessary oar WN gt Engine Break In
51. f necessary w Automatic Compression Release Installation 1 Slide spring onto shaft 2 Apply engine oil to release lever shaft Stop pin 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 Preload approx 1 4 lowest position and install the release lever shaft 6 5mm pre winding the spring approximately 1 4 6 5mm If Camshaft Is Installed In The Engine 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 installed actuator ball will be held in the out position It is important to note that spring pressure is very light Polaris Sales Inc 3 57 4 99 ENGINE ES33PF 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
52. ft Ibs 6 348 kg m 6mm 6 ft Ibs 828 kg m 4 99 3 102 Polaris Sales Inc ENGINE ES33PF EH50PL Engine Assembly Cont Cylinder Head Installation Clean the gasket surfaces on the cylinder head and cylin der Remove all traces of old gasket material Refer to disassembly photos 1 Install the cam chain tensioner guide Be sure bottom X g ee aes j R n pr Guide in end of guide is located properly in crankcase ca he 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 The following procedure must be used to torque the cylinder head properly Torque all bolts evenly in a criss cross pattern Torque bolts to 22 ft Ibs 3 04 kg m Torque bolts to 51 ft Ibs 7 04 kg m Loosen bolts evenly 180 1 2 tum Loosen bolts again another 180 1 2 tum Torque bolts to 11 ft Ibs 1 52 kg m From this point tighten bolts evenly 90 1 4 turn Finally tighten another 90 1 4 tum Install two 6mm bolts and torque to 6 ft Ibs 828 kg m Polaris Sales Inc 3 103 4 99 ENGINE ES33PF EH50PL Engine Cam Chain Camshaft Installation Install the cam chain
53. g into rope housing reinstall retainer plate lock washer and bolt 4 Check recoil and ratchet operation 5 When reinstalling assembly onto engine use Loctite 518 Gasket Eliminator between the flywheel housing and crankcase Polaris Sales Inc 3 25 4 99 ENGINE EC38PL Engine Disassembly 1 Remove the six bolts retaining the starter assembly and flywheel cover 2 Remove starter pulley and flywheel nut 3 Hold flywheel with holder tool and remove flywheel nut Flywheel Holder PN 8700229 w Holder Ni 4 For starter removal remove bolts retaining starter bracket on PTO side and two bolts A on mag side 5 Remove flywheel using puller Flywheel Puller PN 2871043 4 99 3 26 Polaris Sales Inc ENGINE EC38PL Engine Disassembly Cont 6 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 200 Watt alternator shown at right 7 Remove six cylinder head bolts using a 12 mm socket Note the position of the bleeder plug for the coolant system Polaris Sales Inc 3 27 4 99 ENGINE EC38PL Engine Disassembly Cont Reassembly Note The 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 cyl inder 400L Head Gas
54. he new mechanical seal must be installed after the crankcases are assembled using a special tool See Mechanical Seal Installation Polaris Sales Inc 3 89 4 99 ENGINE ES33PF EH50PL 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 passage 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 S 70mm 2 755 driver For crankshaft main bearings S 46mm 1 810 For counter balancer bearings S 28mm 1 100 For pump shaft bearing 4 99 3 90 Polaris Sales Inc Assembly Cont End Play Inspection Adjustment ENGINE ES33PF EH50PL Engine Before reassembling the crankcase the following steps should be performed to determine the amount of crank shaft 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 load the bearings which may lead to premature bearing failure Crankshaft End Play Adjustment 1 Make sure all bearings are firml
55. iagra Oil filter Oil feed to filter From filter to crankshaft One way valve Top fitting is oil feed or intake from bottom of tank Thermo valve allows oil to by pass cooler when cold Hose Fitting Lower hose fitting on engine x oO Screen Fitting Oil Tank gt ls Bottom of Tank 7 E Hose Fitting aa ers Upper on engine EJ y 1 Hoon Crankcase Oil Passage Prevents oil from draining Oil Pump into crankcase Feed with engine ee One Way Valve Delivery Pipe 7 A Crankcase Oil Pump Oil Pickup Oil Gallery Scavenging Screen Crankcase Small End Bearing Balance Gears Cylinder Sleeve 7 st Indirect viy v Lubrication sh vas Large End Bearing Main Bearing Through Front Left Oil Filter Cylinder Head Bolt Passage Oil Passage Indirect GS In Cylinder Lubrication 1 Crankcase Stator Plate spk dell ke Oil Gallery Bushing Polaris Sales Inc 3 45 4 99 ENGINE EH50PL Lubrication Oil Flow Oil Flow EH50PL The chart on page 3 47 describes the flow of oil through the EH50PL 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 passage to the one way valve When the engine is off the one way valve closes to prevent oil in the tank from
56. il and a center expander section The top rail has a locating tab on the end which fits into a notch A in the upper oil ring land of the piston 5 Remove the top rail first followed by the bottom rail 6 Remove the expander 4 99 3 74 Polaris Sales Inc ENGINE ES33PF EH50PL Engine Cylinder Inspection 1 Remove all gasket material from the cylinder sealing surfaces 2 Inspect the top of the cylinder for warpage using a straight edge and feeler gauge Cylinder Warpage 002 05 mm 3 Inspect cylinder for wear scratches or damage 4 Inspect cylinder for taper and out of round with a telescoping gauge or a dial bore gauge Measure in two 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 1 2 Down From Top of Cylinder 1 2 Up From Bottom Polaris Sales Inc 3 75 4 99 ENGINE ES33PF EH50PL Engine Engine Disassembly Cont 5 Record measurements If cylinder is tapered or out of round beyond 002 the cylinder must be re bored oversize or replaced Cylinder Taper Limit 002 Max Cylinder Out of Round Limit 002 Max Standard Bore Size Refer to Page 3 5 3 8 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 ma
57. ing 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 pro cess and should not be re used Pump Shaft Oil Seal Water Pump Mechani cal Seal Removal Engine Disassembled NOTE The water pump mechanical seal can be re moved without removing the engine Refer to Water Pump Mechanical Seal Installation 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 hand side crankcase 2 Pry out the oil seal noting the direction of installation with the spring side facing IN toward inside of case 3 Drive the water pump mechanical seal out of the crankcase from inside to outside Note T
58. ket pictured at right NOTE Small hole in cylinder above exhaust port is a decompression aid for starting 8 Remove oil line from intake boot 9 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 10 Remove cylinder 11 Refer to page 3 35 3 40 to inspect parts Reassembly Note Due to limited clearance a torque adaptor must be used to apply specified torque to base nuts upon reassembly 12 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 13 Remove piston pin using Polaris piston pin puller PN 2870386 14 Refer to page 3 35 3 40 to inspect parts 4 99 3 28 Polaris Sales Inc ENGINE EC38PL Engine Disassembly Cont 15 Remove slotted left hand thread crankshaft nut using Polaris tool PN 2870967 Reassembly Note Refer to page 3 1 for torque spec ification upon reassembly Clockwise to Remove 16 Remove five crankcase bolts A indicated in the photo at right with a 12 mm socket 17 Remove four nuts and two bolts B indicated in the photo at right with a 10 mm socket 18 Remove cover tapping lightly with a soft face hammer if necessary 19 Using a 10 mm socket remove the impeller nut C 20 Slide water pump assembl
59. 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 4 99 3 46 Polaris Sales Inc EH50PL Engine Internal passage to camshaft front left head bolt Bottom fitting is oil exhaust or return to tank EH50PL Oil Flow Chart Top of Oil Tank Oil Tank EN Screen Fitting Union Fitting Upper Bottom of Tank Crankcase Oil Gallery Cam Shaft Journal Cam Shaft Journal Prevents oil from draining into crankcase with engine off One Way Valve Delivery Pipe Oil Filter Crankcase Oil Gallery Sprocket Chain Rocker Arm Rocker Shaft Through Cylinder Stud Front Left Delivery Pipe Delivery Pipe ENGINE EH50PL Oil Flow Diagram Oil filter Oil feed to filter From filter to crankshaft One way valve Top fitting is oil feed or intake from bottom of
60. lip installation tool PN 2870773 with open end down Slide portion of tool barrel over driver 18 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 19 Rotate driver to complete engagement of clip 20 Visually inspect the C clip to be sure it is fully seated in the groove 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 with 2 Stroke oil 23 Reinstall piston pin Warm piston crown lightly with heat gun to ease pin installation CAUTION Do not overheat piston Do not apply heat to piston rings or loss of temper may result 24 Repeat Step 17 through 20 for other C clip ENGINE EC25PF EC28PF Engines Toward Flywheel C clip retainers open end should be straight up or straight down Forward Polaris Sales Inc 3 19 4 99 ENGINE EC25PF EC28PF Engines Assembly Cont 25 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 a When installing base gasket use gasket eliminator no
61. ll 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 Oil Pump Bolt Torque 6 ft Ibs 828 kg m 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 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 Crankcase Bolt Torque Crankcase Sealant 14 ft Ibs 19 20 Nm PN 2871557 Polaris Sales Inc 3 95 4 99 ENGINE EH50PL Engine Water Pump Mechanical Seal Installation EH50PL 1 Clean the seal cavity to remove all traces of old s
62. lobe using a micrometer Compare to specifications on page 3 5 3 8 Lobe height 4 Measure camshaft journal outside diameter O D Measure ID of camshaft journal bore Journal O D 6 Calculate oil clearance by subtracting journal OD from journal bore ID Compare to specifications on page 3 5 3 8 Journal 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 4 99 3 58 Polaris Sales Inc ENGINE ES33PF EH50PL Engine Engine Disassembly Cont Cylinder Head Exploded View ES33PF ES33PF 1 Remove the two 6mm flange bolts from cylinder head Polaris Sales Inc 3 59 4 99 ENGINE ES33PF EH50PL Engine Cylinder Head Exploded View EH50PL 1 Remove the two 6mm flange bolts A from cylinder head EH50PL 4 99 3 60 Polaris Sales Inc Engine Disassembly Cont 2 Loosen each of the four cylinder head bolts evenly 1 8 turn each time in a criss cross pattern until loose 3 Remove bolts A 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 ES33PF New head gasket must be installed with sealant facing upward Cylinder Head Inspection 1 Thoroughly clean cylinder head surface to remove all traces of gasket material an
63. longer If 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 Theradiator cap relief pressure is 13 Ibs for all models Polaris Sales Inc 3 9 4 99 ENGINE Cooling System 5 Blade Fan Air Cooled Models Fan assembly shown is 6 Blade Fan Liquid Cooled Models for air cooled models rib faces engine on air cooled and liquid cooled Red dot faces engine Washer used here on metal fan blades Recommended Coolant Fan motar bracket 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 engine damage Polaris Premium 60 40 Antifreeze Coolant is recommended for use in all cooling systems and F orward comes pre mixed and ready to use La 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 C 5 Fan Switch Off 210 F 99 C 10 154 F 68 C 5 175 F 79 Fan Switch On 235 F 113 C 174 F 79 C 190 F 88 Hot Light
64. lot and make a light cut 4 Inspect the cut area of the seat S If the contact area is less than 75 of the cir cumference of the seat rotate the pilot 180 and make another light cut S If the 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 S If the 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 S 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 If using an interference angle 46 apply black permanent marker to the entire valve face A 6 Insert valve into guide and tap valve lightly into place A a few times 4 99 3 68 Polaris Sales Inc Valve Seat Reconditioning cont 7 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 or slightly above and must be the proper width S If the indicated seat contact is at the top edge of the valve face and conta
65. lts and torque to specifications Cam Sprocket Bolt Torque 6 ft Ibs 828 kg m Verify TDC mark in timing inspection hole and alignment pin is directly in line with crankshaft to camshaft centerline Refer to Ill on following page Apply Loctite 515 or 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 ENGINE ES33PF EH50PL Engine Single TDC Mark Aligned Polaris Sales Inc 3 105 4 99 ENGINE ES33PF EH50PL Engine Assembly Camshaft Timing Sprocket Alignment Pin Single TDC Mark Aligned TDC Mark Rotation Ra ae tc gt Do Not Use Advance Marks 4 99 3 106 Polaris Sales Inc ENGINE ES33PF EH50PL Engine Assembly Cont Cam Chain Tensioner Installation 1 Release the ratchet pawl A and push the tensioner plunger B all the way into the tensioner body 2 Install the tensioner body with a new gasket and tighten the bolts Tensioner Bolt Torque 6 ft Ibs 828 kg m 3 Install the spring new sealing washer and tensioner plug Tensioner Plug Torque 17 ft Ibs 2 346 kg m 4 Slowly rotate engine two to three revolutions and re check cam timi
66. ly Cont 4 Using the special socket remove the crankshaft slotted nut A NOTE The slotted nut is a left hand thread 5 Remove cam chain drive sprocket B 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 Inspect for Areas of Tooth Wear or Damage The one way valve prevents oil from draining out of the oil 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 One Way Valve Spring Free Length Std 1 450 3 68 cm Inspect valve for wear Check seat area for nicks or foreign material that may prevent proper sealing of valve 4 99 3 82 Polaris Sales Inc Crankcase Separation 1 Remove flange bolts 10 from magneto side crankcase evenly in a criss cross pattern Separate crankcase by tapping with a soft faced hammer in reinforced areas Tap lightly on balancer gear with a brass drift through the hole in the crankcase if necessary to ensure the balancer shaft stays in the PTO side crankcase Watch the gap along the crankcase mating surface and separate the crankcase evenly It may also be necessary to tap the oil pump shaft lightly to separate the crankcas
67. ly 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 Polaris Sales Inc 3 87 4 99 ENGINE ES33PF EH50PL Engine Engine Disassembly Cont 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 Use a feeler gauge to measure the connecting rod big end side clearance Connecting Rod Big End Side Clearance Refer to page 3 5 3 8 4 Place the crankshaft in a truing stand or V blocks and measure the runout on both ends with a dial indicator Refer to page 3 40 Max Runout 0024 06 mm 5 Measure the connecting rod big end radial clearance Big End Radial Clearance Refer to page 3 5 3 8 6 Inspect the crankshaft main bearing journals for scoring and abnormal wear 4 99 3 88 Polaris Sales Inc ENGINE ES33PF EH50PL Engine Engine Disassembly Cont Crankcase Bear
68. n 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 Wn NNnNNNNNNNNHNNHNNUnNNUnNNUHnNVHWWHWNUnWNWN WH 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 Restricted air filter main or pre cleaner Improperly assembled air intake system Restricted engine breather system Oil contaminated with fuel Restricted
69. n until flush with the out er edge of the seal bore Press Water Seal Flush Bearin 4 99 3 34 Polaris Sales Inc ENGINE Top End Component Parts Inspection 2 Stroke Engines Assembly Oil Check Valve Testing EC 38PL EC38PL Apply 2 7 PSI pres The oil pump check valve on the EC38PL engine must be sure to the line fitting To engine 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 cylinder NOTE Refer to page 3 22 for check valve testing on 250 and 300cc engines 400 Check Valve Polaris Sales Inc 3 35 4 99 ENGINE Piston Cylinder Clearance 2 Strokes Cylinder Inspection Measurement CAUTION Careless handling of the cylinder pistons or rings may cause irreparable damage Handle these parts with 1 2 Down From Top of Cylinder care Do not damage the gasket surfaces during the cleaning operation Inspect cylinder for wear scratches or damage Ifno damage is evident measure cylinder for taper and out of round with a telescoping gauge and micrometer 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 Record all measurements 1 2 Up From Bottom Pi
70. ne 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 cylinder Oil Check Valve Testing EC 28PF 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 SNot used with plastic drive gear S Must be used with metal drive gear ap J Plastic 3084825 Ca subs to jo Q Metal 3083429 Bushing Bushing end play adjustment shims EC25PF Apply 2 7 PSI pres sure to the line fitting To engine 250 Engine EC28PF Apply 2 7 inches of mercury VACUUM to the line fitting 300 Engine Engine oil check valve should release at 2 to 7 PSI Pump Bleed Screw 4 99 3 22 Polaris Sales Inc ENGINE EC25PF Engine Recoil Disassembly 1 Remove four 6mm 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 p
71. ned as shown in the photo at right Grease the center hole and seal in the flywheel housing Install ratchet pawl bracket The alignment pin and the square drive on the bracket shaft should properly align in the spring hook While holding the bracket tight against the spring hook flip the flywheel housing over and thread the reel onto the pawl bracket shaft Clamp the ratchet pawl bracket in the corner of the jaws of a vise Firmly hand tighten the reel 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 Install the rope housing over the reel Holding the flywheel housing with one hand rotate the rope housing clockwise until the rope is completely re wound Rotate the housing three more turns and reinstall bolts Reinstall pawl return spring Check recoil and ratchet operation When reinstalling assembly onto engine use Loctite 518 Gasket Eliminator between the flywheel housing and crankcase 4 99 3 24 Polaris Sales Inc ENGINE EC25PF Engine Recoil Assembly 1 Pass the free end of recoil rope through the reel housing 2 Holding the flywheel housing with one hand rotate the reel clockwise until the rope is completely re wound 3 Rotate the housing three more turns and install the pawl return spring with the large end of the spring goin
72. ng Stator Flywheel and Starter Drive Installation NOTE The stator flywheel starter drive and recoil can be assembled with the engine in the frame Stator 1 Apply a light film of grease to the crankshaft seal Apply molybdenum disulfide grease or assembly lubricant to the crankshaft bushing 2 Install a new 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 NOTE This is a static timing mark Strobe timing should be performed after start up Polaris Sales Inc 3 107 4 99 ENGINE ES33PF EH50PL Engine Assembly Cont 5 Torque bolts evenly to specification Stator Plate Bolt Torque 5 1 6 5 ft Ibs 68 88 kg m 6 Seal stator wire grommet with 3 Bond 1215 or equivalent sealer Flywheel 1 Install flywheel washer and nut Torque flywheel to specification Flywheel Nut Torque 58 72 ft Ibs 7 85 9 81 kg m 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 Starter Drive Grease
73. ng 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 EC25PF PN 3083629 008 2 mm and PN 3083630 004 1 mm For EC28PF and EC38PL PN 3084778 008 2 mm and PN 3084779 012 3 mm Polaris Sales Inc 3 17 4 99 ENGINE EC25PF EC28PF Engines Assembly Cont 9 10 11 12 13 14 15 Remove crankcase end seals and thoroughly clean the case half mating surfaces Heat PTO side case half until it is hot to the touch Reinstall crankshaft into heated case Allow case to cool to room temperature before proceeding Heat mag side case half until it is hot to the touch Place Loctite 518 gasket eliminator on one of the case halves Reinstall the mag side half Torque case half attaching bolts in three steps to torque specified on page 3 1 Follow the torque pattern shown on page 3 3 NOTE Before proceeding check piston to cylinder clearance ring end gap and cylinder honing procedures on page 3 36 3 38 16 Install piston rings beveled side up onto piston 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 Piston Ring Cutaway Keystone Ring 4 99 3 18 Polaris Sales Inc Assembly Cont 17 Position C clip onto driver of C c
74. nspect 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 at a time from the inside out Pull knot out of of recoil reel Untie knot Remove rope from reel ENGINE ES33PF EH50PL Engine Recoil Starter Polaris Sales Inc 3 111 4 99 ENGINE ES33PF EH50PL Engine Recoil Starter Recoil Assembly CAUTION Be sure to wear a face shield and eye protec tion when performing this procedure To install a new spring 1 Place spring in housing with the end positioned so the spring spirals inward in a counterclockwise direction See photo at right 2 Hold spring in place and cut retaining wire To reinstall an old spring 1 Hook outer tab in place in recoil housing and wind spring in a counterclockwise direction one coil at a time while holding the installed coils in place 2 Lubricate the spring with light lubricant such as Premium All Season Grease To complete recoil assembly 1 Route rope through guide bushing in recoil housing and into reel Tie a secure knot in end of the rope 2 Wind rope counterclockwise onto the reel as viewed from ratchet side of reel 3 Lock rope into notch on outer edge of reel 4 Apply a small amount of grease or equivalent to the center post of the housing and the bushing 5 Install reel into housing making sure the spring drive tab on the reel engages the spring and the reel
75. ntil the counterbalance assembly is completely removed Reassembly Note Counter Balance Shaft For reassembly of counterbalancer shaft after crankcase assembly heat areas D and E and press the ba lancer and bracket back into place 4 99 3 30 Polaris Sales Inc ENGINE EC38PL Engine Disassembly Cont 27 Remove crankcase bolts i Inspect oil pump drive gear and bearing Replace shaft as an assembly 2 Inspect crankshaft runout and components See Ce page 3 40 28 Tap cases apart with a soft faced hammer Shims used to adjust crankshaft end play Follow procedure on page 3 16 3 17 Align marks upon reassembly Polaris Sales Inc 3 31 4 99 ENGINE EC38PL Engine Connecting Rod Side Clearance 29 Remove crankshaft Inspect connecting rod side clearance 30 Measure clearance between lower rod and counterweight with a feeler gauge connecting rod big end side clearance New measurement should be between 016 020 4 5 mm Clearance should not exceed 036 9mm Connecting Rod Side Clearance Standard 016 020 4 5mm Service Limit 036 9mm Connecting Radial Clearance 31 Measure the total movement of the connecting rod big end bearing Movement should not exceed 0013 033mm 32 Remove seals from crankcase 33 Clean crankcase thoroughly and install new seals until flush with edge of seal bore Reassembly Notes 1 Before a
76. oil tank vent Polaris Sales Inc 3 113 4 99 ENGINE 2 Stroke Engine Troubleshooting Action Possible Cause Engine turns over but does not start Engine does not turn over Engine runs but will not idle Engine idles but will not rev up Engine has low power Piston failure Scoring Melted piston top Skirt breakage Excessive smoke and carbon buildup Engine coolant found in counter balance assem bly Liquid cooled mod els No fuel Dirt in fuel line or filter 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 stuck Plugged carb pilot system Carb misadjusted Choke not adjusted properly Low compression Crankcase leak Broken throttle cable Obstruction in air intake Incorrect carb jetting ETC limiting speed 1989 and newer Reverse speed limiter limiting speed Incorrect ignition timing Restricted exhaust system Cylinder piston and ring wear or damage check compression PVT not operating properly Plugged exhaust Lack of lubrication 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 Oil pump cable not allowing
77. over the crankshaft CAUTION Serious engine damage may re sult if the camshaft is 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 Camshaft Timing 1 Apply Polaris Premium Starter Drive 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 57 2 Install the camshaft with the lobes facing downward and the sprocket alignment pin facing upward 3 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 installing the cam Do not use the advance marks See Ill on next page Single TDC Mark Aligned 4 99 3 104 Polaris Sales Inc 4 10 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 A is directly in line with the crankshaft camshaft centerline B Install the sprocket on the camshaft Apply Loctite 242 to the cam sprocket bo
78. pare to specifications on page 3 5 3 8 Replace spring if either measurement is out of specification 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 ENGINE ES33PF EH50PL Engine Valve Spring Free Length Coil Fatigue Squareness ong Hitel i Polaris Sales Inc 3 63 4 99 ENGINE ES33PF 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 A 4 Inspect split keeper groove for wear or flaring of the keeper seat area B NOTE The 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 Compare to specifications on age 3 5 3 8 pag Measure valve stem in several places y A 4 99 3 64 Polaris Sales Inc ENGINE ES33PF EH50PL 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 Me
79. r 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 positioned upward See text for 4 stroke oil control ring upper rail installation Use the information below to identify pistons and rings Engine Model No Oversize Available Piston Length Standard Piston si Identification EC25PFE 08 09 10 11 13 3W 4W EC28PFE 01 02 25 70 mm 50 eee F EC38PLE 04 05 25 78mm 38A 50 EC38PLE 06 07 08 09 25 78mm 38B 50 EH42PL 02 25 66mm 50 EH50PLE04 06 08 09 25 72mm C 50 Pistons and rings marked 25 equal 25mm 0101 oversized Pistons and rings marked 50 equal 50mm 0201 oversized Pistons and rings marked 10 equal 1 0mm 0401 oversized 250 engines only Piston Clearance Specifications 2 Stroke Engines NOTE See page 3 5 3 8 for 4 Stroke engine service data Machine Model Engine Cyl Bore Stroke Piston Ring End Piston Clearance Svc Model Disp in mm in mm Gap Installed Clearance Limit CCs in mm in mm in mm Trail Blazer EC25PF 244 2 8346 72 2 362 60 009 018 0011 0021 006 15 Trail Boss 23 46 03 05 Xpress 300 EC28PF 283 2 935 74 5 2 561 65 012 022 0012 0026 006 15 Xplorer 300 31 56 03 07 Xplorer 400 EC38PLE 379 3 270 83 2 758 70 007 015 0023 0037
80. r to Chapter 5 S Fuel Tank Cover Front Cab Refer to Chapter 5 S Fuel Tank Refer to Chapter 4 Disconnect oil pump cable Disconnect spark plug high tension lead Remove springs from exhaust pipe and remove pipe Drain coolant and engine oil where applicable Remove air pre cleaner and duct Remove airbox Remove carburetor Insert a shop towel into the carburetor flange to prevent dirt from entering the intake port Loosen auxiliary brake master cylinder mount if necessary for clearance Remove center chain guard on chain drive AWD models Remove center drive and driven sprocket bolts and remove chain and sprockets as an assembly Refer to PVT System to remove outer clutch cover drive belt drive clutch driven clutch and inner cover Starter motor Note ground cable location Mark positive cable mounting angle and remove cable Remove transmission linkage rod s from gear selector and secure out of the way Disconnect coolant temperature sensor wire where applicable Remove engine to chassis ground cable where applicable Remove all engine mount nuts and or engine mount plates Remove engine through right side of frame 4 99 3 12 Polaris Sales Inc ENGINE Engine Installation Engine Installation Notes After the engine is installed in the frame review this checklist and perform all steps that apply General Items 1 Install previously r
81. r wear Replace if worn or damaged Polaris Sales Inc 3 55 4 99 ENGINE ES33PF EH50PL Engine Engine Disassembly Cont 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 Inspect for Areas of Tooth Wear or Damage Retainer Sleeve 4 99 3 56 Polaris Sales Inc ENGINE ES33PF EH50PL Engine Engine Disassembly Cont Automatic Compression Release Removal Inspection NOTE The automatic compression release mecha nism can be inspected and serviced without removing the camshaft from the cylinder head The actuator ball in the camshaft is not replaceable Replace the cam shaft as an assembly if the actuator ball is worn or dam aged 1 Check release lever shaft for smooth operation throughout the entire range of rotation The spring should hold the shaft weight against the stop pin In this position the actuator ball will be held outward in the compression release mode 2 Remove release lever shaft and return spring Inspect shaft for wear or galling 4 Inspect lobe on end of release lever shaft and actuator ball for wear and replace i
82. rough the hose and into the crankcase inlet oil passage and then pumps the oil through another passage to the one way valve Note The one way valve closes under light spring pressure when the engine is off to prevent oil in the tank from draining into the crankcase The valve requires very little maintenance After passing through the one way valve 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 located in the stator plate 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 orifice in the end of the crank pin to the PTO end main bearings and counterbalancer gears
83. 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 4 99 3 52 Polaris Sales Inc ENGINE ES33PF EH50PL Engine Rocker Arm Shaft Inspection 1 Mark or tag rocker arms to keep them in order for assembly ES33PF Inspect surface of follower 2 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 Wave washer 3 Measure O D of rocker shaft Inspect it for wear or damage Compare to specifications on page 3 5 3 8 Polaris Sales Inc 3 53 4 99 ENGINE ES33PF EH50PL Engine Rocker Arm Shaft Inspection cont 4 Measure I D of each rocker arm and compare to specifications on page 3 5 3 8 5 Measure I D of both rocker arm shaft supports and visually inspect surface Compare to specifications on page 3 5 3 8 6 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 4 99 3 54 Polaris Sales Inc ENGINE ES33PF EH50PL Engine Camshaft Removal 1 Remove camshaft sprocket inspection cover 2 Loosen three camshaft sprocket bolts 3 Remove camshaft end cap and O Ring 4 Inspect camshaft end cap thrust face fo
84. ssembling the crankcase calculate crankshaft end play and place shims between as required Follow procedure on page 3 16 3 17 Refer to page 3 40 for crankshaft inspection 4 99 3 32 Polaris Sales Inc ENGINE EC38PL Engine Reed Valve Inspection 1 Measure reed stop height A Recommended stop height is 350 9 mm 2 Measure the air gap of each reed valve petal with a feeler gauge B as shown in the photo at right The air gap should not exceed 015 4 mm NOTE Anearly sign of reed valve failure may be hard starting and poor low end performance 3 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 1 Apply a small amount of putty or clay to the top of one impeller blade A 2 Assemble impeller and bearing seal housing on balancer shaft Polaris Sales Inc 3 33 4 99 ENGINE EC38PL Engine Water Pump Impeller Clearance cont 3 Reinstall case gasket and bolt case together in areas B and C as indicated on the photo at right 4 Carefully remove case cover 5 Remove water pump impeller and check clearance measurement Acceptable clearance measured with a dial caliper is between 020 040 05 1 cm CAUTION
85. ston Inspection Measurement 2 Stroke 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 calculate clearance with a new piston and recondition the cylinder or replace piston as necessary Refer to page 3 4 for piston to cylinder clearance specifications Measure 3 8 10 mm up from bottom of skirt 4 99 3 36 Polaris Sales Inc ENGINE Piston Ring Installed Gap Piston Ring Installed Gap 1 Position each piston ring 1 21 1 3 cm from the top of the cylinder using the piston to push it squarely into place Measure installed gap with a feeler t both the top and bottom of the cylinder i PA gauge at bo e top and bottom of the cylinder Cylinder 25 50mm Feeler Gauge NOTE A difference in end gap between the bottom and top of the cylinder indicates cylinder taper The cylinder should be measured for excessive taper and out of round Replace rings if the installed end
86. t 3 Measure total width of main bearings with bearings Add the thickness of the spacer between the bearings on EC28 engines Record total measurement 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 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 Subtract thickness of flat stock and record the measurement on line B below Measure magneto side case half using the same procedure Record measurement on line C below Remember to subtract thickness of flat stock 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 If adjustment is required determine the amount of spacers needed to achieve proper end play Install spacers on crankshaft followed by PTO bearings Total from Step 1 2 and 3 or from Step 1 only if PTO bearings were installed A Step 5 Result B Step 6 Result C Line B Line C D Line D Line A End Play Subtract Target End Play 012 3mm Shim Thickness Required ENGINE EC25PF EC28PF Engines Measure total width Po Spacer used on EC28 engine only Correct crankshaft end play is 008 016 2 4 mm End play is adjusted by addi
87. tall 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 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 balancer drive gear and crankshaft main bearing area 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 C Ring Profile ae Second Tang Outward 4 99 3 100 Polaris Sales Inc
88. 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 valve s Clean cylinder head valves and camshaft oil supply passage A thoroughly If oil passage blind plug was removed apply 3 Bond 1215 or equivalent sealer to the threads and install torquing to 8 ft Ibs 1 1 kg m CAUTION Do not allow sealant to enter oil passage Spray electrical contact cleaner into oil passage and dry using compressed air Cylinder Head Assembly CAUTION Wear eye protection during assembly NOTE Assemble the valves one at a time to maintain proper order 1 w Install new valve seals on valve guides Apply engine oil to valve guides and seats Coat valve stem with molybdenum disulfide grease Install valve carefully with a rotating motion to avoid damaging valve seal YEL 4 99 3 70 Polaris Sales Inc Cylinder Head Assembly Cont 5 Dip valve spring and retainer in clean engine oil and install spring with closely spaced coils toward the 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
89. tremely close tolerances the bearings must be inspected visually and by feel Look for signs of discoloration scoring or galling Turn the outer race of each bearing The bearings should turn smoothly and quietly The inner race of each bearing should fit tightly on the crankshaft The outer race should be firm with minimal side to side movement and no detectable up and down movement Replace any loose or rough bear ings Refer to crankshaft inspection on page 3 40 ENGINE EC25PF EC28PF Engines Polaris Sales Inc 3 15 4 99 ENGINE EC25PF EC28PF Engines Engine 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 Or 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 4 99 3 16 Polaris Sales Inc Assembly Con
90. ximum cylinder measurement obtained in step 5 above Piston to Cylinder Clearance Refer to Page 3 5 3 8 Piston Piston Pin Piston O D Refer to Page 3 5 3 8 4 99 3 76 Polaris Sales Inc ENGINE ES33PF EH50PL Engine Engine Disassembly Cont 3 Measure piston pin bore Piston Pin Bore Refer to Specifications on Page 3 5 3 8 4 Measure piston pin O D Replace piston and or piston pin if out of tolerance Piston Pin O D Refer to Specifications on Page 3 5 3 8 Piston Pin Measurement Locations 5 Measure connecting rod small end ID Connecting Rod Small End I D Refer to Specifications on Page 3 5 3 8 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 Piston Ring to Groove Clearance Refer to Specifications on Page 3 5 3 8 Polaris Sales Inc 3 77 4 99 ENGINE ES33PF EH50PL Engine Engine Disassembly Cont Piston Ring Installed Gap 1 Place each piston ring inside cylinder using piston to push ring squarely into place as shown at right Piston Ring Feeler Gauge 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 m
91. y 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 Polaris Sales Inc 3 29 4 99 ENGINE EC38PL Engine Disassembly Cont 21 Remove collar O ring guide washer and Crankshaft Gear crankshaft gear i Guide Washer O Ring j Collar 22 Remove oil pump assembly D 23 Remove two bolts securing the counter balance retaining bracket A using a 10 mm socket CAUTION Complete Step 20 and 21 before removing the counterbalance assembly or damage may result 24 Attach counterbalance puller B onto counter balance shaft and position as shown in the photo at right Reassembly Note The retainer bracket must be in position on the counterbalance assembly before the assembly is installed in the crankcase Punch marks C on both gears must be across from each other dur ing reassembly See photo three at right Counter Balance Puller PN 2870968 25 Heat counter balance bearing areas D and E on the crankcase with a heat gun for approximately one to two minutes WARNING Oil and gasoline are highly flammable and explosive under certain conditions Use extreme caution when using a heat gun or propane torch in this environment 26 Once these areas are thoroughly heated add tension to the puller by turning the large nut Continue tensioning the puller u
92. y seated in the both Mag and PTO crankcase 2 Measure the distance from the PTO crankcase mating surface to the main bearing using a dial caliper and a straight edge 3 Subtract the thickness of the straightedge from the measurement obtained in Step 2 and record PTO Case Depth Polaris Sales Inc 3 91 4 99 ENGINE ES33PF EH50PL Engine Crankshaft End Play Adjustment cont 4 Measure the distance from the Magneto crankcase mating surface to the main bearing using the same method and record 5 Subtract the thickness of the straightedge from the measurement obtained in Step 4 and record Mag Case Depth 6 Add the readings recorded in Step 3 and Step 5 and record below Total Case Width 7 Measure the width of the crankshaft at the bearing seats with a micrometer or dial caliper and record Crankshaft Width 8 Subtract the Crankshaft Width measured in Step 7 from the Total Case Width recorded in Step 6 and record below Total End Play 9 Subtract the thickness of the existing shim from the result of step 8 to determine if a different shim is required The result must be within the specified range listed below Crankshaft End Play 008 016 02 04 cm 4 99 3 92 Polaris Sales Inc ENGINE ES33PF EH50PL Engine Assembly Cont Counter Balancer Shaft End Play Adjustment 1 Make sure all bearings are firmly seated in the crankcase 2 Measure the width of the counter
93. you are replacing a plastic drive gear with a metal one you must also order and install thrust washer PN 3083428 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 22 250 300 Models Refer to Illustration on following page 1 Lubricate and install pump drive gear thrust washer pump drive gear and bushing into crankcase Make sure parts are completely seated 2 Measure the distance from the pump bushing to the crankcase pump mounting surface Record this as measurement A Example 4 8mm Refer to example below 3 Measure distance from pump shoulder to pump mounting flange Record this as measurement B Example 3 9mm_Refer to example below 4 Subtract measurement B Step 3 from measurement A Step 2 See example below The difference between these two measurements is the end play the pump bushings will have without shims Subtract the target clearance from measured and add shims equal to that amount EXAMPLE A Step 2 4 8 B Step 3 3 9 9 Target clearance 2 6mm Total thickness of 3 7mm shims required Spacer shim part numbers PN 3083671 15 mm 006 PN 3083672 3 mm 012 PN 3083673 6 mm 024 Polaris Sales Inc 3 21 4 99 ENGINE EC25PF EC28PF Engine Assembly Oil Check Valve Testing EC25PF The oil pump check valve on the EC25PF engi

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