2015 120 Honda Manual
Contents
1. Min 1 058 20 031 NO GO 0 0180 NO GO Thru All 3 PLCS Thru All VATA KZA 0 070 NO GO o E 0 0250 NO GO Max 0 169 N 6 PLCS Thru All Min 0 155 QMA GX 120 Dump Tube Must be stock Honda GX120 Dump Tube NO ALTERATIONS L The butterfly screw the butterfly and the throttle shaft must not be removed from the carburetor Any evidence of tampering will be a disqualification and suspension M Decimal equivalents of numbered size drills chart on page 20 ENGINE COOLING SHROUDS A All pieces of the stock engine cooling shroud must be properly installed B There must be no addition or subtraction of any material from the shrouding except for the covering of the switch hole any material Starter cup may be altered to be used as washer retainer for the cooling fan C Shrouds can be repainted to either the stock Honda Red or Black no other colors allowed Remove engine cooling shrouds Remove valve cover Zero Dial Indicator after exhaust bump 0 050 ref 3 Maximum valve lift will be checked from the top of valve spring retainer Valves may be adjusted to zero clearance or shims may be installed to create zero clearance This may dictate making special shims as it is difficult to insert feeler gauge blades so as not to interfere with indicator contracts on retainer Valve lift NO Intake 0 245 maximum Exhaust 0 255 maximum CYLINDER HEAD HEAD GASKET VALVES SPRINGS Remove cylinder head H2. aligning marks Turn the flywheel clockwise and stop at 20 degrees BTDC or 0 065 0 066 BTDC on your indicator Make another mark on the block casting that aligns with your mark on the flywheel Remove dial indicator so it will not be damaged by engine rotation Install timing light to a battery if not self powered and clamp inductive pickup to spark plug wire Wire should be hooked to standard spark plug gapped to 0 025 Using a drill with an extension that is cut off or turned to fit drill place socket on flywheel nut and rotate engine in clockwise direction Fire the timing light and observe If the reference mark on the flywheel is between the two marks on block casting that are TDC and 0 066 or 20 degrees BTDC the timing is legal If mark is not between marks on block casting when rotating the engine will be disqualified Other pictures and text indicate methods of detecting which particular part is not in spec 17 Tech officials have the right to tech any or all cars in any class at their discretion Tech Officials follow the same chain of command as all officers of OMA as follows Local Regional National I E Regional tech officials can tech at any event at their region and National Tech Officials can tech at any event in OMA National Tech Director is final authority on all tech issues DECIMAL EQUIVALENTS OF NUMBER SIZE DRILLS Size in Size in Size in Size in No Decimals No Decimals No Decimals No Decim
3. maximum overall length of 1 500 inches Pipe stub must be inserted into exhaust pipe at least 0 750 inches and will have minimal exhaust leakage Muffler to be used will be 4 to 8 hp Briggs amp Stratton part number 294599 or equal equivalent Muffler will be internally unaltered except that the round cup shaped baffle may be welded to the perforated baffle without moving its original location Threads will not be removed from muffler Exhaust pipe will be a maximum of 1 000 inches outside diameter with a length of 20 0 to 26 0 including a threaded pipe coupler to welded to the end of the pipe in order to screw muffler in place so that muffler may be removed for inspection Pipe coupler will be a standard unaltered 34 NP threaded coupler Length will be 1 000 inches minimum to 2 250 inches maximum There will be no steps or tapers in exhaust pipe or flange assembly Exhaust pipe length will be measured by using a small diameter hose inserted though pipe to measure over all length Flange and coupler will be included in the overall length when measuring pipe No coating of any type may be applied to the interior of any part of the exhaust system The intent of this rule is to have all of the exhaust pass through the muffler All measurements are to be taken with the component pieces in the same position as they were installed and on the car 1 All QMA midget mufflers must be Briggs amp Stratton Part 294599 or equivalent No dri
4. 0 511 ref Length 1 854 0 010 ID 0 354 Weight 23 grams minimum CONNECTING ROD Stock Honda rod with no alterations A Connecting rod big end size 1 021 minimum 1 0265 maximum B Pin end bore is 0 5111 ref C Length from bottom of pin bore to top of big end bore will be 2 111 maximum 2 101 minimum D Rod weight with bolts 119 grams or 4 2 oz minimum E No oil grooves on bearing surface of either end F Thai rods may have light sanding marks CRANKSHAFT Stock Honda crankshaft with no alterations Notes A No removal or addition of any metal from or to the crankshaft is allowed B No balancing of the crank is allowed C No oil grooving is allowed on the crank journal D Governor drive gear cannot be removed E Crankshaft drive gear should not be removed This gear is installed by Honda to any accuracy of 2 degree If this gear is not installed to this degree of accuracy engine may not be legal when camshaft is checked by the procedure under engine block F Keyway location must not be altered in any manner H The only cleaning method allowed is on the flywheel side of crankshaft for the purpose of removing calcium rust etc from the exposed end of the crankshaft This Is permitted only from the seal groove out to the end of the thread of the crankshaft where the flywheel bolts on Only a wire wheel may be used in the cleaning process The use of Scotchbrite sandpaper or any othe
5. A approved slotted plate only Failure to use proper restrictor plate alteration of restrictor plate or improper installation of plate in designated classes is cause for immediate DQ and all applicable suspensions will be applied w AmMOO a ee ce Either Japanese or Thailand insulators may be used Gasket thickness 0 025 maximum Restrictor thickness 0 0625 maximum No slotting of holes on any Honda restrictor Insulator gasket thickness 0 025 maximum Novice Restrictor hole size 0 3125 maximum red Plate must have QMA logo Junior Restrictor hole size 0 4375 maximum blue Note blue plate only effective 5 31 10 plate must be dated 06 09 or newer DQ and 30 day suspension Restrictors will be teched by NO GO Gauges effective 5 1 2014 Check for any alterations or worn parts that would allow additional air into engine holes slots perforations spacers loose bolts warped flanges etc Carburetor identification number BE 60 B Thai BE 60 R UT 2 BE99A Check carburetor for alterations Upper choke shaft hole may be sealed with silicone type sealer Two stock Honda intake gaskets may be used between Carburetor and plastic insulator Carburetor Bore Intake end maximum diameter 0 950 Throttle end maximum diameter 0 632 Carburetor venturi bore 0 456 no go This measurement is best made with a no go gauge but may be made using a telescoping gauge as a no go H Main jet and main nozzle
6. MUST BE TIGHT The Pilot Air Jet hole is just inside of this brass piece This needs to be checked with the proper pin type no go gauge The hole at the end of the arrow is the Main Air Jet hole and will be checked using a pin type no go gauge Main Jet Size maximum 70 0 028 no go Jets must be stock unaltered no stepping or funneling of jet Main air jet 0 0394 maximum 60 0 040 no go at back of hole Main jet access passage 0 094 maximum 41 0 096 no go Main nozzle l 2 3 I J Main nozzle bore 0 070 maximum 50 0 070 no go Main nozzle will be checked with a NOGO Gauge 0 429 If gauge goes over dump tube carb is illegal This is best measured using a 0 452 rod type gauge with a 0 429 flat area to be used as a go gauge Air vent holes on the side of the main nozzle must not be plugged Main nozzle must not be fastened into the carburetor body by anything other than the main jet It must not be epoxied or positioned by any other means Slow speed system 1 Pilot jet 0 0138 maximum 79 0 0145 no go 2 Pilot air jet 0 050 minimum 1 25mm 0 0492 go 3 Pilot screw no spec 4 Pilot seat diameter 0 035 maximum 61 0 039 no go 5 Tip of pilot screw 0 019 minimum Float bowl vent 0 118 maximum 31 0 120 no go K Needle valve seat 0 065 maximum 51 0 067 no go Max 1 072
7. Rocker arm studs will be stock Honda They or their mounting position may not be altered in any manner No heli coiling of mounting holes No bending of studs Push rods will be stock Honda and will not be altered in any way Push rod length will be VALVES A Check valves for dimensions and weight Valve seating surface must be factory ground to a single angle only 45 degrees There will be no other angles ground on any part of valve Valves must not be polished lightened or altered in any way B Valve weight Intake 18 grams minimum Exhaust 16 grams minimum C Drawing of valve dimensions Intake Valve followed by Exhaust Valve Note UT 1 Current 120 ex valve part 14721 ZFO 000 Retainer 14773 ZE1 000 and lash cap 14781 ZE1 000 must be used in combination UT 2 New 120 ex valve part 14721 Z4H 00 and Retainer 14771 ZE1 000 must be used in combination no mixing of old and new style parts New style ex valve 14721 Z4H 000 measures 2 470 overall length HEAD Cylinder head will be in as cast and in factory machined condition and there must be no addition of metal or any other substance to the inside or outside of the cylinder head No alteration that could increase valve spring pressure Note Effective 4 1 11 Thailand heads will no longer permitted on the GX 120 engines Any legal Japanese GX 120 head may be used New Gx 120 casting number 13 heads are available from HPD A Measure from flat of head surface d
8. a QUARTER AMIDGETS OF AMERICA f TECH MANUAL HONDA ENGINE RULES GENERAL RACING RULES SPECIFICALLY FOR 120 HONDA CLASS ONLY Jerry Mostek QMA Technical Director First Issued March 30 1996 Updated April 23 2015 2012 Quarter Midgets of America Inc HONDA CLAIM RULE For GX120 QMA Type Engines l All engine claims must follow procedure listed in QMA rulebook Please see Article 6 Section 1 HONDA SUSPENSIONS l All suspensions must follow procedure listed in QMA rulebook Please see Article 6 Section 2 GENERAL RULES l a m Only stock Honda GX120K1 engine and gearbox will be used in this class No aftermarket blocks allowed All parts will be stock Honda specifically made for the Honda GX12OK1 HX2 U S GCAHK Canada GCAAT UY 2 GCBMT Honda replacement block 12000 Z0S 416 IS ALLOWED All stock Honda parts must be used and properly installed with the following exceptions The following listed below gaskets that are coming from Honda are tan amp green will be legal to use Intake Gasket Carb Gasket Side Cover Gasket A Governor System may be partially or fully removed with the exception of the steel drive gear on the crankshaft This gear must remain intact If shaft is removed hole must be plugged Hole can be tapped for thread or epoxy No welding B Factory air cleaner must be removed Any QMA approved air filter may be attached to the outside of air filter adapter Outer wear style o
9. als 1 2280 21 1590 41 0960 61 0390 2 2210 22 1570 42 0935 62 0380 3 2130 23 1540 43 0890 63 0370 4 2090 24 1520 44 0860 64 0360 5 2055 25 1495 45 0820 65 0350 6 2040 26 1470 46 0810 66 0330 T 2010 217 1440 47 0785 67 0320 8 1990 28 1405 48 0760 68 0310 9 1960 29 1360 49 0730 69 0292 10 1935 30 1285 50 0700 70 0280 11 1910 31 1200 51 0670 T1 0260 12 1890 32 1160 52 0635 72 0250 13 1850 33 1130 53 0595 T3 0240 14 1820 34 1110 54 0550 14 0225 15 1800 35 1100 55 0520 15 0210 16 1770 36 1065 56 0465 76 0200 17 1730 37 1040 57 0430 Tf 0180 18 1695 38 1015 58 0420 78 0160 19 1660 39 0995 59 0410 19 0145 20 1610 40 0980 60 0400 80 0135 END 18
10. ck Honda standard size and will not be altered in any way A Oversized pistons must not be used B All three piston rings must be used and installed properly l Top ring Chrome compression ring installed with N or T on rail up Thai rings are marked R No expander under ring 2 Middle ring Oil scraper ring installed with N or T on rail up Thai rings are marked R No expander under ring U Bottom ring Three 3 piece oil rings are allowed Check oil ring expander for alterations that will alter ring tension cutting ends of expander ect Piston may not be knurled grooved or coated Piston weight 106 grams minimum Total Piston weight With rings pin and clips 118 grams minimum Total Piston weight with rings retainers complete with rod pins and bolts 263 grams minimum See drawing for dimensions Gra m oO YTN N MMAQRASLALQOOG IULII ae Mi a NO EK pe A a orn Ar NY HONDA 0 12 PRTOH Tar ii 7 l OLD STYLE TIER HI A Must be stock Honda rings with stock size and configuration Compression and scraper rings may not be collapsed in grove B No decreasing of ring tension by heating machining or any other means F Ring thickness OLD STYLE TIER HI Compression 0 056 min Compression 0 036 min Scraper 0 056 min Scraper 0 036 min Oil Ring 3 piece lower 0 095 min 1 piece 0 097 min 14 WRIST PIN Stock Honda wrist pin and retainer OD
11. ction of metal or any other substance to the inside or outside of the block A Cylinder bore will be 2 366 maximum NOTE All measurements taken at top of bore or very bottom of bore 1 Wear Limits Parts Out Of Service QMA reserves the right to confiscate 120 Honda engine parts deemed illegal or at QMA maximum wear limits EXAMPLE Cylinder Bore will be 2 366 Max All measurements taken at top of bore or very bottom of bore parallel to crank 90 degrees from crank Any cylinder block that has one measurement over QMA maximum wear limits will be taken out of service If no measurements exceed QMA maximum wear limits the part of block will not be confiscated Handler has the right to have confiscated parts returned to them but will be rendered unusable Cylinder bore will not be bored oversize Cylinder bore will not be re sleeved Cylinder bore position will not be moved or tipped in any manner Cylinder block deck surface finish non tech Machined surface of block down to thrust face of cam boss 3 226 minimum 3 240 maximum Machined surface of block down to bearing face 3 427 minimum 3 442 maximum H Oil level sensor will be intact and unaltered Wires may be externally disconnected or cut off TADA Q PROCEDURE FOR CHECKING TIMING A With degree wheel or indicator located at 0 degrees or TDC mark both the flywheel and some fixed point such as right hand side of aluminum block casting right above flywheel with
12. e replaced with larger or smaller screw No heli coiling of mounting hole Jaw 11 E Ignition coil or its position other than air gap may not be altered in any way Coil mounting bolts must be stock and cannot be altered in any way to advance or retard timing Coil attaching bolts will be stock 6mm cap screw I 1 16 long There can be no more than 3 8 of unthreaded portion of bolt that does not measure 0 230 diameter This restricts movement of coil to a position that could make ignition timing illegal Ifa coil support mount becomes stripped it is permissible to heli coil However only one leg may be repaired if both legs are heli coiled the block becomes illegal F All nylon blades on the cooling fan TIER HI Black Only Pins No metal removal or addition to flywheel is permitted Flywheel weight will be 1550 grams minimum Flywheel diameter magnet area 6 285 minimum A stock Honda spark plug cap wire end and resistor must be used Any automotive type spark plug with 4 reach maximum is allowed Note Tapered seat spark plugs are illegal Race DQ only Ignition coil air gap is no longer a tech item Stated dimensions are recommended for safe operation will be 0 008 minimum 0 024 maximum No plug indexing washers allowed If temperature sensor is used under spark plug factory washer may be removed 12 GEAR BOX AND RING GEAR A Gear box may not be altered in any way May be rotated to d
13. ead gasket thickness 0 040 minimum thickness of inner rim Measure from head surface to top of valve head Intake maximum 0 210 minimum 0 178 Exhaust maximum 0 210 minimum 0 178 This is best done with a depth micrometer or a bridge type dial indicator Bridge type does not require removing carbon from head surface See photo on next page Combustion chamber cc 10cc ref with stock spark plug Remove valves Retainer A Inspect retainers for alteration that would increase valve spring pressure Both intake and exhaust must have stock Honda retainers Exhaust valve only can have lash cap and corresponding retainer B Thickness of retainer will be Intake 0 228 minimum Exhaust 0 241 minimum C Flange thickness of retainer will be Intake 0 110 maximum Exhaust 0 070 maximum D From flat of flange to machined surface Intake 0 148 minimum Exhaust 0 165 minimum E All Valve oil seals must be removed 1 The use of valve seals is illegal and will result in event DQ only NO suspension VALVE SPRINGS Valve springs will be stock Honda springs and will not be altered in any way Wire diameter 0 071 maximum Outside diameter of spring 0 790 maximum Number of total coils 5 3 Spring pressure 11 LBS maximum at 0 812 GOP eh r E Stacked length will be 0 394 maximum ROCKER ARMS PUSH RODS STUDS Rocker arms will be stock Honda and will not be altered in any way
14. ered b Material may not be added to throttle stop area of black plastic piece or carb body C Rear mounting brackets for Honda fuel tank may be removed D The starter cup that is behind the flywheel retaining nut can be cut away to leave only the flat washer back piece that retains cooling fan E The keyed end of the sun gear shaft may be shortened drilled and tapped or machined for snap ring F Heli coiling threads for shrouds all valve cover existing throttle mounting holes oil drain and fill holes one of the coil bolts and side cover bolts is allowed Dowel holes are not to be modified or relocated also one carburetor mounting bolt Pie Honing and deglazing of the bore is allowed Lapping the valves is allowed Blocking Air Flow No device may be used that will or appear that it may impede airflow into the engine cooling system This may require that the engine be run at a speed above idle by the tech personnel at the scale after the car has qualified or raced CARBURETOR GX160 CARBURETOR MAY BE USED IN HEAVY HONDA ONLY SEE GX160 MANUAL FOR CARB SPECS Remove Carburetor A Check for restrictor if applicable and placement Restrictor must be installed between carburetor and carburetor insulator with stock Honda gasket on each side of restrictor Only stock Honda insulator gasket between black plastic insulator and head Air passageway in insulator will not be altered in anyway All Junior Honda s must use the blue QM
15. esired position B Ring gear may not be altered in any way with the exception of the keyed end of shaft that may be shortened drilled and tapped or machined for snap ring grove No other machining drilling grinding etc to ring gear Keyway may be cut deeper D Ring gear may not be altered in any way including polishing or use of any compound or abrasive on gear shaft where bearings ride E Two gaskets maximum between gear box halves CRANKCASE COVER Remove crankcase cover A Cover must be as cast and in factory machined condition and there must be no addition or subtraction of metal or any other substance to crankcase cover B Crankcase cover gasket must be stock Honda Only one gasket may be installed with a maximum thickness of 0 025 C Critical dimensions are thrust face of camshaft holder and position of crank bearing Place a straight edge over crank bearing and cam boss thrust face These surfaces should be level Maximum tolerance will be 0 005 There will be no alterations to crankcase cover This includes any alteration to crank bearing and camshaft holder position and height in an attempt to alter valve timing PISTON WRIST PIN AND PISTON RINGS Remove rod and piston triangle or boss on top of piston must point toward push rods piston wrist pin and rings must be absolutely stock and not altered in any manner 13 TIER HI Round Boss OLD STYLE Triangle PISTON NOTES Piston will be sto
16. inish of such chamber is illegal ENGINE BLOCK This engine block must be as cast and in factory machined condition There must be no addition or subtraction of metal or any other substance to the inside or outside of the cylinder block crankcase cover crankshaft rod piston pin rings flywheel or coil with the following exceptions Removal of rear gas tank brackets is permitted Removal of governor Governor system may be partially removed with the exception of the steel gear on the crankshaft This gear must remain intact Governor arm and shaft may be removed tied forward or altered to accommodate throttle linkage or return springs C Addition of brackets fittings etc to accommodate throttle linkage tachometer temperature gauge is allowed D Cylinder Block deck surface non tech Check bore 2 366 maximum NOTE All measurements taken at top of bore or very bottom of bore Wear Limits Parts Out Of Service QMA reserves the right to confiscate 120 Honda engine parts deemed illegal or at QMA maximum wear limits EXAMPLE Cylinder Bore will be 2 366 Max All measurements taken at top of bore or very bottom of bore parallel to crank 90 degrees from crank Any cylinder block that has one measurement over QMA maximum wear limits will be taken out of service If no measurements exceed QMA maximum wear limits the part of block will not be confiscated Handler has the right to have confiscated parts returned to them but will be rendered un
17. lling holes in the baffles Inside seam of baffle must be straight edged NOTE Some seams may not be parallel in baffle You cannot cut off the threaded flange if it is to be used in Honda It is OK to weld a washer or nut on the flange for a place to apply safety wire Choke butterfly and shaft must be removed Hole may be filled only with silicone Or old shaft cut down Oil level switch may be disconnected but switch assembly must remain intact in crankcase Gearbox may be rotated to any desired position Main jet in carburetor may be a maximum of 70 Max Some jets will be silver in color they are legal Off On ignition switch may be removed and hole covered Any material no welding moO K All pin measuring gauges are plus tolerance L Exhaust oxygen sensor or temp Sensor attached to any part of Honda exhaust system is illegal M Valve seals are illegal N Cryogenics of any Honda part is illegal O Note Taking parts out of service Reference Wear Limits in Engine Block Internal section P DQ Only Not Suspension for Exhaust Air Filter Adapter and Spark Plug or valve seal Silicone or any type of sealer or epoxy only approved area s are choke shaft hole and governor shaft hole multiple ex gaskets or more than 2 carb to insulator gaskets Q R Loose jet is a 30 day suspension UNLESS IT SAYS YOU CAN DO IT DON T DO IT TECH PROCEDURE Modifications or machining of any parts in order to bring them to sta
18. own to valve seat This dimension will be Al Latest head cylinder number 12210 ZH7 415 Maximum 0 265 Minimum 0 250 B Measure from surface of head to top of valve guide This dimension will be 0 925 Max Intake 0 925 Max Exhaust 0 925 Max Japan heads may be identified by the casting mark shown in photo above C Measure from surface of head to lowest machined area in the bowl of the port This dimension will be Intake 1 064 maximum Exhaust 1 010 maximum D Thickness of head This will be measured from valve cover surface to head gasket surface at the side at a position in line with upper intake amp exhaust flange bolt Maximum 2 917 Minimum 2 911 Note Most heads in the field have a thickness of 2 914 INTAKE AND EXHAUST PORTS A Ports will be as cast and in factory machined condition and there must be no addition or subtraction of metal or any other substance to the inside or outside of the cylinder head B No alterations of any kind to be made to the intake or exhaust port C This includes any grinding polishing etching sand blasting or glass beading to interior surface D Valve seats must be a stock single 45 degree angle Multi angle valve seats are not permitted Valve seats must not be replaced E Intake and Exhaust ports at valve Intake maximum 0 752 minimum 0 745 Exhaust maximum 0 675 minimum 0 665 Note Cleaning of the combustion chamber or changing the f
19. r compounds or abrasives is illegal No material may be added or removed from crankshaft Crankshaft main journal at flywheel and gearbox ends may not be altered in any way Heat treat rings on splined end of crank is no longer a tech item as long as crank still makes spec And has not been modified 15 THAILAND CRANKSHAFT JAPAN CRANKSHAFT CAMSHAFT Camshaft must be stock Honda with no alteration of any kind Notes A There will be no additions to or subtractions from any part of the camshaft B Compression release will remain intact and unaltered Be C Lobe center angle will not be altered by any means D Lobe profile will not be altered in any way CAMSHAFT SPECIFICATIONS INTAKE EXHAUST Heel to Heel 0 864 0 869 Heel to Heel 0 865 0 870 Heel to Peak 1 079 1 093 Heel to Peak 1 081 1 095 Length thrust flange to thrust flange 3 135 minimum 3 142 maximum Cam bearings are 0 547 0 551 and unaltered under 547 minimum take out of service no DQ TAPPETS Tappets must be stock Honda with no alterations Base diameter 0 909 minimum no maximum spec C Stem diameter 0 312 minimum D Base thickness 0 073 minimum 0 090 maximum w gt E Length 1 180 minimum 1 220 maximum F Weight 16 grams minimum 16 ENGINE BLOCK INTERNAL The engine block must be in an as cast and factory machined condition and there must be no addition or subtra
20. r equivalent can be used over carburetor only with no adapter The approved air filter adapter may be run with or without an air filter Any air filter may be used with adapter as long as there are no devices inside the air filter or adapter I E Springs not allowed Hose from valve cover must go into a catch can We are using outerwear to define a style not brand name 1 The use of air filters during qualifying at asphalt events is illegal The Senior Tech Official reserves the right to allow filters at any event that it s deemed necessary Stock Honda fuel tank must be removed Recoil starter must be removed Pull cup may be cut down for washer Must use original cup Exhaust Stock Honda muffler will be removed Mounting flange may be cut off of muffler and used as adapter flange Any transition from the D shape of the exhaust port to round must take place with in the thickness 0 250 max of the flange This applies to all exhaust systems No steps or tapers allowed pipe must be Ilpiece continuous pipe from flange or slip nipple to muffler coupler No sections of pipe welded together BUTT WELDS grind marks are allowed past 0 250 flange area No suspension for exhaust flange or pipe infraction just disqualification If an after market flange is used maximum allowable flange thickness will be 0 250 inches If slip on type flange assembly is used pipe stub will be a maximum 0 880 inches outside diameter tubing with a
21. ted minimum or maximum specs blueprinting is not legal 1 External visual check of engine for required components Pipe and muffler shrouds and sheet metal oil level sensor this can be partially observed from outside NOTES A Factory air cleaner must be removed Any approved air filter may be attached to the outside of air filter adapter Outer wear style or equivalent can be used over carburetor only with no adapter The approved air filter adapter may be run with or without an air filter Any air filter may be used with adapter as long as there are no device s may be used inside the air filter or adapter that will alter the airflow into the carburetor I E Springs not allowed Hose from valve cover must go into a catch can We are using outerwear to define a style not brand name 1 Air cleaner adapter will be maximum ID 2 250 and a maximum of 1 375 long in length flange thickness 0 375 max flange ID 1 000 minimum hole size straight walled flat bottomed and parallel with carburetor using existing air cleaner mount holes 2 The use of air filters during qualifying at asphalt events is illegal The Senior Tech Official reserves the right to allow filters at any event that it s deemed necessary B Any type throttle linkage may be utilized Carburetor will be unaltered with the exception of the black plastic piece on upper end of throttle shaft this is the only part in the carburetor that can be alt
22. usable Use dial caliper to check bore Check stroke 1 659 Maximum 1 640 Minimum Measure amount that piston is up or down from block surface at T D C This will be measured at edge or highest part of piston not in center or relieved area This dimension will be 0 000 Max NO PISTON POP UP Install degree wheel on flywheel Install pointer in order to read degrees Locate accurate T D C This should be done with a positive stop type fixture and not established with indicator alone P Cam will be checked with indicator reading off the top end of tappets which will provide zero clearance The inverted radius of the top of the tappet presents some problem to get accurate readings and to prevent binding of indicator stem Indicator holder and positions are very critical in this operation Zero indicator on base circle of cam Be sure that compression release does not affect zeroing exhaust indicator Zero dial indicator after exhaust bump ref Turning engine in normal rotation clockwise facing flywheel take reading at specified opening Readings must fall between specified degrees on the following chart 10 CAMSHAFT PROFILE LIMITS Intake Degrees 0 050 10 14 ATDC 0 100 26 30 ATDC 0 150 45 49 ATDC 0 180 SPLIT 0 200 71 76 ATDC MAX LIFT 0 227 Peak 104 107 ATDC 0 200 135 141 ATDC 0 180 SPLIT 0 150 162 167 ATDC 0 100 180 185 ATDC 0 050 197 4 201 ATDC E
23. xhaust Degrees 0 050 206 1 2 210 2 BTDC 0 100 189 1 2 193 2 BTDC 0 150 170 2 174 2 BTDC 0 180 SPLIT 0 200 144 148 BTDC MAX LIFT 0 229 Peak 107 4 110 BTDC 0 200 70 73 4 BTDC 0 180 SPLIT 0 150 44 1 4 47 14 BTDC 0 100 26 29 14 BTDC 0 050 9 12 2 BTDC FLYWHEEL FAN AND IGNITION SYSTEM Caution should be used when removing flywheel Do not hit with hammer or other heavy objects Service manual show flywheel to be removed with commercially available 6 puller Another method is inertia type knocker that threads onto crankshaft end The transistorized magneto ignition is fixed at 20 degrees BTDC and may not be altered in anyway Firing must not exceed 0 0665 or 20 degrees BTDC Quick check Turning flywheel clockwise if the leading edge of the depression of flywheel rim where the magnet is mounted is not still under the right hand coil leg at 0 065 BTDC it is probably illegal and should be checked further If timing needs to be checked further see page 19 A Flywheel keyway or its position must not be altered Key should fit snugly in crank if key has been altered it is a DQ regardless of timing White magnet flywheel and stock or offset key is DQ and 30 day suspension Factory Key only may not be deleted or altered in any way Magnet and its position may not be altered in any way Magnet retaining screw may not be altered in any way Screw may not b
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