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2008 Sportsman 500 Service Manual Chapter 3

1. To install a new spring 1 2 Place spring in housing with the end positioned so the spring spirals inward in a counterclockwise direction See photo at right 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 Lubricate the spring with light lubricant such as Premium All Season Grease PN 2871423 To complete recoil assembly 1 2 3 52 Route rope through guide bushing in recoil housing and into reel Tie a secure knot in end of the rope Wind rope counterclockwise onto the reel as viewed from ratchet side of reel Lock rope into notch on outer edge of reel Apply a small amount of grease or equivalent to the center 9 NO post of the housing and the bushing Install reel into housing making sure the spring drive tab on the reel engages the spring and the reel is fully seated in the housing Apply downward pressure on the reel and rotate counterclockwise approximately 6 7 turns to pre wind the spring Continue rotating counterclockwise until rope on outer edge aligns with rope guide bushing Release rope from notch and allow reel to rewind completely If more pre wind is required place rope in notch and add additional turns of pre wind Install ratchet pawl and return spring with long leg of spring engaged in re
2. 001 003 0254 0762 mm Counter Balancer Shaft Removal Inspection Wear Limit 004 1016 mm 1 Remove the shim washer A from the counter balancer shaft 10 Measure clearance between outer feed rotor and pump body with a feeler gauge J 2 Note the alignment dots on the balancer and crankshaft gears the marks must be aligned during reassembly z ERA f GA Rotor Tip Clearance Std 005 127 mm Wear Limit 008 2032 mm 11 Measure rotor tip clearance with a feeler gauge 12 Remove inner and outer feed rotor and pump chamber body 13 Repeat measurements for scavenge rotor 14 Remove inner and outer scavenge rotor and inspect pump shaft for wear 3 34 ENGINE 3 Turn the shaft until balancer counter weights clear the crankshaft and remove the balancer shaft from the crankcase Inspect the balancer drive gear and pump shaft drive gear 5 Replace the shaft if gear teeth are abnormally worn or damaged 6 Inspect the balancer shaft bearings NOTE Due to extremely close tolerances and minimal wear the balancer shaft ball bearings must be inspected visually and by feel Look for signs of discoloration 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 inner race should be firm with minimal side to side movement and no detectable up and
3. The piston may have an identification mark or the piston may not have an identification mark for piston placement If the piston has an identification mark follow the directions for iston placement below If the piston does not have an identification mark the direction for placement of the piston does not matter Note the directional and identification marks when viewing the pistons from the top The letter F gt P or must always be toward the flywheel side of the engine The other numbers are used for identification as to diameter length and design Four stroke engine rings are rectangular profile See text for oil control ring upper rail installation Use the information below to identify pistons and rings Engine Oversize Piston Standard Model No Available mm Length Piston Identification EH50PLE 25 72mm C 50 EH42PLE 25 66 mm B 50 Pistons and rings marked 25 equal 25mm 010 oversized Pistons and rings marked 50 equal 50mm 020 oversized 3 6 Cooling System Specifications Sensor 18 5 ft lbs 25 Nm THERMISTOR READING DURING OPERATION ss Approx Reading Condition Min Max Temperature Temperature 37 3 39 2 kQ 68 F 20 C System 2 25 Quarts Capacity 2 13L Radiator Cap Relief 13 PSI 89 6 kpa Pressure ENGINE Cooling System A WARNING Never remove radiator cap when engine is warm or ho
4. 008 203 mm 4 Measure the OD of the starter drive shaft on both ends and record 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 Inspect gear teeth on starter drive Replace starter drive if gear teeth are cracked worn or broken Flywheel Stator Removal Inspection 1 2 Remove flywheel nut and washer Install Flywheel Puller PN 2871043 and remove flywheel Do not thread the puller bolts into the flywheel more A CAUTION than 1 4 or stator coils may be damaged Mark or note position of stator plate on crankcase Remove bolts and carefully remove stator assembly being careful not to damage crankshaft bushing on stator plate Replace crankshaft seal A 3 31 ENGINE 7 Remove large sealing O Ring from outer edge of stator section of chain Replace if worn past service limit plate Chain Service Limit 5 407 13 7 cm 4 Using the special socket remove the crankshaft slotted nut NOTE The crankshaft slotted nut is a left hand thread 5 Remove cam chain drive sprocket and woodruff key from crankshaft 6 Inspect sprocket teeth for wear or damage Inspect woodruff key for wear 8 Replace any worn or damaged parts One Way Valve Removal The one way valve prevents o
5. damaging valve seal 5 Dip valve spring and retainer in clean engine oil and install spring with closely spaced coils toward the cylinder head E a a 2 6 Place retainer on springs and install valve spring compressor Compress spring only enough to allow split keeper installation and prevent loss of spring tension Install split keepers with the gap even on both sides 7 Repeat procedure for remaining valve 8 When all valves are installed tap lightly with soft faced hammer on the end of the valves to seat the split keepers 3 26 Valve Sealing Test 1 Clean and dry the combustion chamber area Pour a small amount of clean high flash point solvent into the intake port and check for leakage around each intake valve The valve seats should hold fluid with no seepage 3 Repeat for exhaust valves by pouring fluid into exhaust port NOTE The valves share a common rocker arm and must be adjusted using two feeler gauges 1 Insert 006 feeler gauge s between end of exhaust valve stem and adjuster screw s 2 Loosen locknut s and turn adjuster screw s until there is a slight drag on feeler gauge s The Valve Clutch Adjuster Tool PA 44689 can be used to adjust the 500 engines valves NOTE Both feeler gauges should remain inserted during adjustment of each valve VALVE CLEARANCE 006 15 mm 3 When clearance is correct hold adjuster screw and tighten locknut securely 4 Re check the valve clear
6. the engine to avoid damage to the chain drive sprocket teeth or tensioner blade 15 Tighten the cylinder bolts in three steps in a criss cross pattern and torque to specifications 16 Install the two 6 mm bolts and torque to specifications Cylinder Bolt Torque 10 mm 46 ft been Nm 6 mm 6 ft Ibs 8 Nm Cylinder Head Installation Clean the gasket surfaces on the cylinder head and cylinder Remove all traces of old gasket material efer to disassembly photos 1 Install the cam chain tensioner guide Be sure bottom end of guide is located properly in crankcase 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 followin 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 30 Nm Torque bolts to 51 ft Ibs 70 Nm Loosen bolts evenly 180 1 2 turn Loosen bolts again another 180 1 2 turn Torque bolts to 11 ft Ibs 15 Nm From this point tighten bolts evenly 90 1 4 turn Finally tighten another 90 1 4 turn Install two 6 mm bolts and torque to 6 ft Ibs 8 Nm Guide in recess Cam Chain Camshaft Installation Install the cam chain over the crankshaft A CAUTION Serious engine damage ma
7. 022 0035 055 090 mm Limit 0039 10 mm Cylinder Head Surface warpage limit 0020 05 mm Standard Height 3 870 98 3 mm Valve Seat Contacting width In Std 028 7 mm Limit 055 1 4 mm Ex Sd 039 1 0 mm Limit 071 1 8 mm Valve Guide Inner diameter 2362 2367 6 0 6 012 mm Protrusion above head 689 709 17 5 18 0 mm Valve Margin Thickness In Std 039 1 0 mm Limit 031 8 mm Ex Std 047 1 2 mm Limit 031 8 mm Valve Stem diameter In 2343 2348 5 950 5 965 mm Ex 2341 2346 5 945 5 960 mm Stem Oil Clearance Std In 0014 0024 035 062 mm Ex 0016 0026 040 067 mm Limit 0059 15 mm Overall length In 3 976 101 0 mm Ex 3 984 101 2 mm Valve Spring Overall Length Std 1 654 42 0 mm Limit 1 575 40 0 mm Squareness 075 1 9 mm 3 4 ENGINE Engine Service Data Cylinder Piston Connecting Rod EH50PLE Cylinder Surface warpage limit mating with cylinder 0020 0 05 mm head Cylinder bore Std 3 6221 3 6228 92 00 92 02 mm Taper limit 0020 0 05 mm Out of round limit 0020 0 05 mm Piston clearance Std 0006 0018 0 015 0 045 mm Limit 0024 0 060 mm Boring Limit 020 5 mm Piston Outer diameter Std 3 6204 3 6215 91 970 91 985mm 0098 25 mm OS
8. 3 6304 3 6310 92 21 92 23 mm 0197 50 mm OS 3 6403 3 6407 92 46 92 47 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 Piston Ring Piston Ring Installed Top ring Std 0079 0138 20 36 mm ep Limit 039 1 0 mm Second Std 0079 0138 20 36 mm ring Limit 039 1 0 mm Oil ring Std 0079 0276 0 20 0 70 mm Limit 059 1 5 mm Piston Ring Standard clearance Top ring Std 0016 0031 0 040 080 mm e fon Limit 0059 15 mm Second Std 0012 0028 0 030 0 070 mm ring Limit 0059 15 mm Connecting Connecting rod small end ID 9058 9063 23 007 23 020 mm Rod Connecting rod small end radial Std 0003 0010 007 026 mm larange Limit 0020 05 mm Connecting rod big end side Std 0039 0256 1 65 mm Peaiance Limit 0315 80 mm Connecting rod big end radial Std 0004 0015 011 038 mm cid Limit 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 3 5 ENGINE GENERAL ENGINE SERVICE Piston Identification
9. Cylinders may be wet or dry honed erase upon the hone manufacturers recommendations Wet honing removes more material faster and leaves a more distinct pattern in the bore NOTE See next page for more information on honing Honing To Oversize CAUTION If cylinder wear or damage is excessive it will be necessary 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 CAUTION 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 finish honing Refer to piston to cylinder clearance specifications before honing Complete the sizing with fine grit stones to provide the proper cross hatch finish and required piston clearance 3 EXAMPLE OF CROSS HATCH PATTERN ENGINE 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 e 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
10. centered or cylinder centered on 1390 and to bring the stones approximately 1 2 1 3 cm above and below the bore at the end of each stroke 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 ine around the ports will expand causing uneven ore After honing has been completed inspect all port Opening areas for rough or sharp edges Apply a slight chamfer to all ports to remove sharp edges or burrs paying particular attention to the corners of the intake and exhaust ports Cleaning the Cylinder After Honing Itis 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 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 4 Cycle Lubricant 3 10 Crankshaft Straightening Lubricate the bearings and aon te crankshaft securely in the Crankshaft Truing Stand PN 2870569 Refer to the illustrations below Crankshaft Truing Stand PN 2870569 NOTE The rod pin position in relation to the dial indicator position tells you what action is required to straighten the shaft HIGH 0
11. connected to the valve bottom cutters to narrow the seat stem If the seat is too narrow widen using the 45 cutter 20 Rotate the valve rapidly back and forth until the cut sounds and re check contact point on the valve face and smooth Lift the valve slightly off of the seat rotate 1 4 turn seat width after each cut and repeat the lapping process Do this four to five times until the valve is fully seated and repeat process for the Valve Seat Width other VAES Intake Std 028 G mm Limit 055 1 4 mm Exhaust Std 039 1 0 mm Limit 071 1 8 mm Seat Width 21 Clean cylinder head valves and camshaft oil supply passage A thoroughly 22 If oil passage blind plug was removed apply Crankcase Sealant PN 2871557 or equivalent sealer to the threads Bottom 60 or 75 Seat 45 or 46 and install torquing to 8 ft lbs 11 Nm Top 30 A CAUTION Do not allow sealant to enter oil passage 23 Spray electrical contact cleaner into oil passage and dry using compressed air 3 25 ENGINE Cylinder Head Assembly A CAUTION Wear eye protection during assembly NOTE Assemble the valves one at a time to maintain proper order hit hy Install new valve seals on valve guides Apply engine oil to valve guides and seats Coat valve stem with molybdenum disulfide grease PEPA Install valve carefully with a rotating motion to avoid
12. down movement Crankshaft Removal Inspection 7 Remove the shim washer A from the crankshaft 8 Support the PTO side crankcase and crankshaft press the crankshaft out Be careful not to damage the crankcase mating surface or connecting rod 9 Use a feeler gauge to measure the connecting rod big end side clearance Connecting Rod Big End Side Clearance Std 0039 0256 1 65 mm Limit 0315 80 mm 10 Place the crankshaft in a truing stand or V blocks and measure the runout on both ends with a dial indicator Max Runout 0024 06 mm 11 Measure the connecting rod big end radial clearance Big End Radial Clearance Std 0004 0015 011 038 mm Limit 0020 05 mm 12 Inspect the crankshaft main bearing journals for scoring and abnormal wear 3 35 ENGINE Crankcase Bearing Inspection Remove the seal from the PTO side crankcase Inspect the crankshaft main bearings balancer shaft bearings and pump shaft bearing Ne 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 inner race should be firm with minimal side to side movement and no detectable up and down movement 3 Support the crank
13. from recoil housing L TDC T Mark Rotation p Advance Marks To position crankshaft at Top Dead Center TDC on compression stroke 2 Rotate engine slowly in the direction of rotation 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 SS Z 2 4 Align single TDC mark on flywheel with projection in inspection hole and the cam sprocket pin facing upward aligned with the camshaft to crankshaft center line 3 14 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 to loosen and remove tensioner 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 ENGINE 2 Push ratchet pawl and hold it The plunger should move 2 Inspect each rocker arm cam follower surface If there is smoothly in and out of the tensioner body any damage or uneven wear replace the rocker arm 3 Release ratchet pawl and push inward on plunger It
14. should NOTE Always inspect camshaft lobe if rocker arms are remain locked in position and not move inward worn or damaged 3 Measure O D of rocker shaft Inspect it for wear or damage Compare to specifications A ya 4 Measure free length of tensioner spring Replace spring if excessively worn Compare to specifications 5 Replace entire tensioner assembly if any part is worn or damaged Rocker Arm Shaft Inspection 1 Mark or tag rocker arms to keep them in order for assembly 3 15 ENGINE 4 Measure ID of each rocker arm and compare to 3 specifications Loosen three camshaft sprocket bolts Rocker Shaft Oil Clearance Std 0008 0021 020 054 mm Limit 0039 10 mm 5 Measure I D of both rocker arm shaft supports and visually inspect surface Compare to specifications 6 Subtract rocker shaft O D from rocker arm amp shaft support I D This is the oil clearance Compare to specifications 7 Inspect rocker adjuster screws for wear pitting or damage to threads of the adjuster or locknut Replace all worn or damaged parts NOTE The end of the adjuster screw is hardened and cannot be ground or re faced 5 Inspect camshaft end cap thrust face for wear Replace if Camshaft Removal worn or damaged 6 Place a clean shop towel in the area below cam chain 1 Remove thermostat housing 2 Remove camshaft sprocket inspection cover 7 Slide camshaft inw
15. stone seat reconditioning equipment can also be used Keep all valves in order with their respective seat 0000 Good Too Narrow Uneven Wide 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 circumference of the seat and the seat must be the proper width all the way around If the seat is uneven compression 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 narrow heat transfer from valve to seat is reduced and the valve may overheat and warp resulting in burnt valves 4 When thoroughly heated place cylinder head on blocks of wood which will allow the old guides to be removed 5 Using valve guide driver drive guides out of the cylinder head from the combustion chamber side Be careful not to damage guide bore or valve seat when removing guides 3 23 ENGINE 6 Place cylinder head on cylinder head table NOTE Be sure cylinder head is still at 212 F 100 C before installing new guides Valve Guide Installed Height Valve Guide Height 689 709 17 5 18 0 mm 7 Place a new guide in the valve guide installation tool and press guide in to proper depth Check height of each guide above the cylinder head A NOTE The guide can also be driven in to the proper depth Inspect the guide closely
16. the crankshaft bushing 2 Install a new O Ring in the oil passage recess in the crankcase 3 Apply 3 Bond 1215 PN 2871557 or an equivalent sealer to the stator plate outer surface and install a new O Ring E 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 5 Torque bolts evenly to specification Stator Plate Bolt Torque 5 6 5 ft Ibs 7 9 Nm 6 Seal stator wire grommet with Crankcase Sealant PN 2871557 or equivalent sealer Flywheel 1 Install flywheel washer and nut Torque flywheel to specification Flywheel Nut Torque 58 72 ft Ibs 78 98 Nm Starter Drive 3 49 ENGINE gear Apply Starter Drive lt a Grease to Bushing Ad 2 Apply starter drive 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 PN 2871460 Rocker Shaft Rocker Arm Assembly Installation 1 Assemble rocker arms rocker shaft and shaft supports Install and tighten rocker arm shaft locating bolt 3 Apply starter drive grease to the cam lobes and cam follower surfaces 4 Rotate the engine until the cam lobes are pointing downward 5 Be
17. 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 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 3 11 ENGINE EH50PL Oil Flow Diagram nternal passage to camshaft front left Went head bolt NS H AA IN
18. use Accessible Components The following components can be serviced or removed with the engine installed in the frame Flywheel Alternator Stator Starter Motor Starter Drive Cylinder Head Cylinder Piston RIngs Camshaft Rocker Arms Cam Chain and Sprockets e Water Pump Water Pump Mechanical Seal The following components require engine removal for service Oil pump Oil Pump Drive Gear e Counterbalance Shaft or Bearing s e Connecting Rod e Crankshaft e Crankshaft Main Bearings e Crankcase It may be necessary to loosen engine mounts and move engine slightly to access water pump Use the Water Pump Mechanical Seal Puller te 2872105 to replace mechanical seal with engine in frame 3 8 Engine Removal TYPICAL Clean work area Thoroughly clean the ATV engine and chassis Disconnect battery negative cable eee Ro Remove the following parts as required e Seat e Left and Right Side Covers Refer to Chapter 5 e Fuel Tank Cover Front Cab Refer to Chapter 5 e Fuel Tank Refer to Chapter 4 Disconnect spark plug high tension lead Remove springs from exhaust pipe and remove pipe Drain coolant and engine oil Remove air pre cleaner and duct Vos Remove airbox 10 Remove carburetor Insert a shop towel into the carburetor flange to prevent dirt from entering the intake port 11 Remove center chain guard on chain drive AWD models 12 Remove center drive and dr
19. 04 1 mm Y y alh HIGH 004 1 mm EHHE Ad B A SUPPORT CRANKSHAFT HERE 1 To correct a situation like the one shown in the illustration strike the shaft at point A with a brass hammer HIGH 002 05 mm HGH 005 i mm 2 To correct a situation like the one shown in the illustration squeeze the crankshaft at points A Use tool from alignment kit HIGH 002 05 mm HIGH 005 13 mm A ENGINE 3 Ifthe 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 NOTE Maximum allowable runout is 0024 Engine Lubrication EH 50PL Oil Type Polaris Premium 4 Synthetic or API certified SH 2W 50 oil Capacity Approximately 2 U S Quarts 1 9 I Filter Wrench PV 43527 Drain Plug Screen Fitting 14 ft lbs 19 Nm If fitting is removed follow oil pump priming procedure Oil Pressure Specification 20 PSI 5500 RPM Polaris 2W 50 Synthetic Engine Hot Oil Pressure Test EH 50PL 1 Remove blind plug on front left cylinder head 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 onl
20. 21 Nm Pattern Oil Drain Bolt 14mm 14 17 19 23 Nm Crankcase Oil Filter Pipe Fitting 20mm 36 43 49 59 Nm Oil Hose Fitting 1 8 Pipe 6 5 11 9 15 Nm Thread Hard Metal Oil Line N A 11 16 ft lbs 15 21 Banjo Fitting Nm Oil Pump 6mm 5 6 5 7 9 Nm Oil Pump Case Screw 5mm 1 5 2 2 3 Nm One Way Valve 11mm 14 19 20 25 Nm Recoil Housing 6mm 5 6 5 7 9 Nm Rocker Cover 6mm 7 8 9 11 Nm Crankcase Rocker Support 8mm 8 10 11 13 Nm Pattern Rocker Adjuster Screw 6mm 6 7 8 10 Nm Water Pump Impeller 6mm 5 6 5 7 9 Nm Nut Water Pump Housing 6mm 5 6 5 7 9Nm Cover Stator Plate 6mm 5 6 5 7 9 Nm Starter Motor 6mm 5 6 5 7 9 Nm Spark Plug 14mm 9 11 12 15 Nm Thermistor 26 2 1 35 3 Nm 3 3 ENGINE Engine Service Data Cylinder Head Valve EH50PLE Rocker Arm Rocker arm ID 8669 8678 22 020 22 041 mm 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 In Std 1 2884 1 2924 32 726 32 826 mm Limit 1 2766 32 426 mm Ex Sid 1 2884 1 2924 32 726 32 826 mm Limit 1 2766 32 426 mm Camshaft journal OD Mag 1 4935 1 4941 37 935 37 950 mm PTO 1 4935 1 4941 37 935 37 950 mm Camshaft journal bore ID Mag 1 4963 1 4970 38 005 38 025 mm PTO 1 4963 1 4970 38 005 38 025 mm Camshaft Oil clearance Std
21. 9 0198 20 36 mm Limit 039 1 0 mm Oil Ri in Std 0079 0276 20 70 mm Limit 059 1 5 mm 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 If the bottom installed gap measurement exceeds the service limit replace the rings If ring gap is below specified limit file ring ends until gap is within specified range NOTE Always check piston ring installed gap after re boring a cylinder or when installing new rings A re bored cylinder should always be scrubbed thoroughly with hot soapy water rinsed and dried completely Wipe cylinder bore with an oil rag immediately to remove residue and prevent rust Crankcase Disassembly NOTE The recoil starter starter motor starter drive flywheel stator cam chain and sprockets can be serviced with the engine in the frame ENGINE 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 Std Pushing ID 4735 4740 11 11 12 04 mm Std Shaft OD 470 472 11 93 11 99 mm Starter Drive Bushing Clearance Std 0015 004 038 102 mm Service Limit
22. AFT COUNTER BALANCE OIL PUMP INSTALLATION 3 40 CRANKCASE ASSEMBLY 0 0 0000 c eee ee 3 41 WATER PUMP MECHANICAL SEAL INSTALLATION 0 00 5 3 41 WATER PUMP MECHANICAL SEAL REMOVAL ENGINE INSTALLED 3 41 ONE WAY VALVE INSTALLATION 0 0 000000 e eee eee eee 3 42 CAM CHAIN DRIVE SPROCKET INSTALLATION 2 00 0 200005 3 43 TENSIONER BLADE INSTALLATION 0 0 000 000 c eee eee eee 3 43 PISTON RING INSTALLATION 0 02 20 00002 cee eee 3 43 PISTON INSTALLATION ooo 3 44 CYLINDER INSTALLATION 1 00 00 0 0022 c cece 3 44 CYLINDER HEAD INSTALLATION 0 0 0 0 0 e eee eee eee ee 3 45 CAM CHAIN CAMSHAFT INSTALLATION 0 00000020 e eee eee eee 3 45 CAMSHAFT TIMING 0 0 0000 aE E a ee 3 46 CAMSHAFT TIMING 0 0 0000 eee eee 3 48 CAM CHAIN TENSIONER INSTALLATION ooooccccococ eee eee eee 3 49 STATOR FLYWHEEL AND STARTER DRIVE INSTALLATION 3 49 ROCKER SHAFT ROCKER ARM ASSEMBLY INSTALLATION 3 50 THERMOSTAT INSTALLATION 0 000002 eee 3 50 OIL PIPES 3 S38 cL Magee dts Bele tats Sheela eta Ae A 3 50 RECO acc IS ae Gat eas gare be e ro a ea ee a Waele Ap atts RECOIL DISASSEMBLY INSPECTION 0 00000000002 e eee eee eee 3 51 RECOIL ASSEMBLY ma cosita ace 3 52 TROUBLESHOOTING cuz ld yikes ba Ry eae woe SPARK PLUG FOULING je on go ti be ged Phe ere Beals hoe 3 53 ENGINE r
23. ENGINE CHAPTER 3 ENGINE SPECIFICATIONS osorno bs 3 3 TORQUE SPECIFICATIONS nir isei derine e A AE A AA 3 3 SPECIAL TOOLS 0 la A ek eae EN 3 3 ENGINE FASTENER TORQUE PATTERNS cococcccccccc 00000 e eee eee 3 3 ENGINE SERVICE DATA cira cria roma eh et eee dd ee asi wi dae are 3 4 ENGINE SERVIGE DATA aeii moneta Sie lc o pals Pe edie da kas 3 5 GENERAL ENGINE SERVIGE 00m Lhradeavasew aon a Peas 3 6 PISTON IDENTIFICATION 02 0 0 000000000 eee 3 6 COOLING SYSTEM SPECIFICATIONS 0 00000 e eee eee eee 3 6 GOOLING SYSTEM 2 05000 opor tal Reece gets ta a 3 7 ACCESSIBLE COMPONENTS 0 000000 c eee eee 3 8 ENGINE REMOVAL TYPICAL 0 000 002 cece eee eee eee 3 8 ENGINE INSTALLATION NOTES 00 000 e eee eee eee 3 9 CYLINDER HONE SELECTION HONING PROCEDURE 3 9 HONING TO OVERSIZE cui oaks titania tee eve wake ee 3 9 CLEANING THE CYLINDER AFTER HONING 0 0 0 00 00 0005 3 10 CRANKSHAFT STRAIGHTENING 0 0000000002 c eee eee eee 3 10 ENGINE LUBRICATION EH 50PL 0 0 000 002 eee eee 3 11 OIL PRESSURE TEST EH DOPL 0 coria a he Pole ee oa 3 11 OIL PUMP PRIMING PROCEDURE 0 00000 c eee ee eee eee 3 11 OIL FLOW EHSOPE 8 foes te ook eds br ae ee ine 3 11 EH50PL OIL FLOW DIAGRAM 0 000002 ee 3 12 EH50PL ENGINE EXPLODED VIEWS 0 0 0 0000 c eee eee 3 13 ENGINE DISASSEMBEY sits tid an c
24. ER Oil Filter ZAS A Oil feed to filter From filter to crankshaft Bottom fitting is oil retains exhaust or return Top fitting is oil to tank feed or intake from bottom of tank Top of Oil Tank Union Fitting Lower EH50PL Oil Flow Chart Oil Tank Screen Fitting Union Fitting Upper y Bottom of Tank Crankcase Oil Pump Oil Gallery Scavenging Oil Strainer Crankcase Oil Hose Crank Sprocket SL Chain Room Smal End A Bearing A gpl Et Sine Si Prevents oil from Feed draining into crankcase with Y engine off Indirect Main Bearing Lubrication PTO One Way Valve Gan Labs qe ean Large End Del P elivery Pipe E Bearing hoof te Cam Shaft Metal A Oil i Journal Jet Oil Filter Crank Pin Through Cylinder A A i Stud Front Left Crankshaft gt yw Delivery Pipe Grankease 3 gt Delivery Pipe Oil Gallery 3 12 ENGINE EH5OPL Engine Exploded Views Cylinder Cylinder Head Crankcase Crankshaft and Piston Valvetrain 3 13 ENGINE ENGINE DISASSEMBLY Cam Chain Tensioner ROCKER ARM CAMSHAFT Removal 1 Remove ignition timing inspection plug
25. Make sure the pump shaft bearing is firmly seated in the Magneto side crankcase Measure the distance from the magneto crankcase mating surface to the bearing using a dial caliper and a straight edge Subtract the thickness of the straightedge and record Install the gear on the oil pump and measure the width of the pump and gear Subtract this measurement from the measurement recorded in Step 2 Subtract the thickness of the existing shim from the result of Step 3 to determine if a different shim is needed See Shaft End Play Spec Oil Pump Shaft End Play 008 016 02 04 cm 3 39 ENGINE ENGINE REASSEMBLY 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 25 mm 985 seal driver until flush with the outer edge of the seal bore 3 Lubricate the seal lip with grease 3 40 Crankshaft Counter Balance Oil Pump Installation Lubricate all bearings with clean engine oil before assembly Use the Crankshaft Water Pump Installation 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 t
26. ach time in a criss cross pattern until loose Journal Camshaft Journal O D Mag amp PTO End 1 4935 1 4941 37 935 37 950 mm Y Se 7 Fa EA s 3 Remove bolts B 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 Camshaft Journal I D to avoid damaging the thread Mag amp PTO End 1 4963 1 4970 4 Remove cylinder head and head gasket 38 005 38 025 mm 4 Measure camshaft journal outside diameter O D 5 Measure ID of camshaft journal bore Calculate oil clearance by subtracting journal OD from journal bore ID Compare to specifications Camshaft Oil Clearance Std 0022 0035 055 090 mm Limit 0039 10 mm NOTE Replace camshaft if damaged or if any part is worn past the service limit NOTE Replace cylinder head if camshaft journal bore is damaged or worn excessively 3 19 ENGINE Cylinder Head Exploded View EH50PL EHSOPL 3 20 ENGINE Cylinder Head Inspection 1 Thoroughly clean cylinder head A surface to remove all traces of gasket material and carbon Ah CAUTION Use care not to damage sealing surface Cylinder Head Warp Cylinder Head Warp Limit 002 05 mm 1 Lay a straight edge across the surface of the cylinder head at several different points and measure warpage by inserting a feeler gaug
27. ance 5 Repeat adjustment procedure if necessary until clearance is correct with locknut secured ENGINE Cylinder Piston Removal and Inspection 4 Remove the two 6 mm cylinder base bolts NOTE Follow engine disassembly procedures to remove valve cover camshaft and rocker arms and cylinder head 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 1 NOTE The bolts are inside the water jacket 6 Tap cylinder lightly with a plastic hammer in the reinforced 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 2 Loosen all four oil pipe banjo bolts and then remove the bolts and eight sealing washers Remove the pipes 3 Loosen hose clamps and remove coolant inlet hose 3 27 ENGINE Piston Removal By hand Placing both thumbs as shown spread the ring open and push up on the opposite side Do not scratch the ring lands 1 Remove circlip Note piston directional arrow pointing toward the right Mag side of engine 3 Repeat procedure for second ring 1 Remove piston circlip and push piston pin out of piston If The oil control ring is a three piece design consisting of a top and necessary heat the crown of the piston slightly with a b
28. ard to allow removal of cam sprocket and remove sprocket from camshaft and chain 3 16 ENGINE 8 Secure cam chain with a wire to prevent it from falling into the crankcase Inspect for Areas of Tooth Wear or Damage 9 Inspect cam sprocket teeth for wear or damage Replace if necessary Decompressor Shaft o Decompressor Ball S Retainer Sleeve 10 Slide camshaft out the PTO side of the cylinder head Automatic Compression Release Removal Inspection NOTE The automatic compression release mechanism can be inspected and serviced without removing the camshaft from the cylinder head The actuator ball C in the camshaft is not replaceable Replace the camshaft as an assembly if the actuator ball is worn or damaged 1 Check release lever shaft A for smooth operation throughout the entire range of rotation The spring B should hold the shaft weight against the stop pin In this position the actuator ball C will be held outward in the compression release mode Remove release lever shaft and return spring Inspect shaft for wear or galling Aw Inspect lobe on end of release lever shaft and actuator ball for wear and replace if necessary 3 17 ENGINE Automatic Compression Release Installation Camshaft Inspection 1 Slide spring onto shaft 1 2 Apply engine oil to release lever shaft The actuator ball must be held outward to allow installation of the release le
29. arter circuit Engine flooded Low compression high cylinder leakage No spark Spark plug fouled Engine Does Not Turn Over Dead battery Starter motor does not turn Engine seized rusted or mechanical failure Engine Runs But Will Not Idle e Restricted carburetor pilot system Carburetor misadjusted Choke not adjusted properly Low compression Crankcase breather restricted Engine Idles But Will Not Rev Up 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 damaged Incorrect ignition timing Restricted exhaust system sticking diaphragm 3 53 ENGINE Engine Has Low Power e Spark plug fouled e Cylinder piston ring or valve wear or damage check compression e PVT not operating properly e Restricted exhaust muffler e Carburetor slide damage vacuum sticking diaphragm e Dirty carburetor Piston Failure Scoring e Lack of lubrication e Dirt entering engine through cracks in air filter or ducts e Engine oil dirty or contaminated Excessive Smoke and Carbon Buildup e Excessive piston to cylinder clearance e Wet sumping e Worn rings piston or cylinder e Worn valve guides or seals e Restricted breather e Air filter dirty or contaminated Low Compression e D
30. case and drive or press the main bearings out of each crankcase 4 Toremove balancer shaft bearings and pump shaft bearing use a blind hole bearing puller NOTE Bearings are stressed during the removal process and should not be re used 3 36 Pump Shaft Oil Seal Water Pump Mechanical Seal Removal Engine Disassembled NOTE The water pump mechanical seal can be removed without removing the engine Refer to Water Pump Mechanical Seal Installation Replace the pump shaft seal and water pump mechanical 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 The new mechanical seal must be installed after the crankcases are assembled using a special tool See Mechanical Seal Installation Crankcase Inspection 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 ENGINE Bearing Installation 4 Measure the distance from the PTO crankcase mating surface to the main bearing using a dial caliper and a NOTE To ease bearing installation warm the straight edge crankca
31. ck 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 Insert valve into guide and tap valve lightly into place a few times ENGINE 16 Remove valve and check where the Prussian Blue NOTE When using an interference angle the seat indicates seat contact on the valve face The valve seat contact point on the valve will be very narrow and is a should contact the middle of the valve face or slightly normal condition Look for an even and continuous above and must be the proper width contact point on the black marker all the way around the oar valve face e If the indicated seat contact is at the top edge of the valve face and contacts the margin area B it is 17 Clean all filings from the area with hot soapy water rinse too high on the valve face Use the 30 cutter to and dry with compressed air lower me vale Seal 18 Lubricate the valve guides with clean engine oil and apply e If too low use the 60 or 75 cutter to raise the oil or water based lapping compound to the face of the seat When contact area is centered on the valve valve Lapping is not required with an interference angle face measure seat width 19 Insert the valve into its respective guide and lap using a If the seat is too wide or uneven use both top and lapping tool or a section of fuel line
32. 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 crankcase Ah 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 mer Remove M g RID crankcase fromthe ETO case 6 Remove the three screws and strainer screen from pump 7 Clean screen thoroughly Oil Pump Removal Inspection p x p nan Remove pump body screw and feed chamber cover 1 Remove pump shaft bearing A and thrust washer B from pump shaft 2 Remove 2 bolts holding pump drive gear C 3 33 ENGINE 9 Measure pump end clearance using a feeler gauge and Oil Pump Assembly straight edge 1 Clean and dry all parts thoroughly Apply clean engine oil to all parts Do not use gasket sealer on the pump body mating surfaces or oil passages will become plugged 2 Install pump shaft and scavenge rotor drive pin 3 Install outer scavenge rotor inner scavenge rotor and scavenge casing 4 Install outer feed rotor and inner feed rotor drive pin 5 Install inner feed rotor and 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 lbs 8 Nm Oil Pump ALS Bolt Torque 6 ft Ibs 8 Nm Pump End Clearance Std
33. e above conditions exist the valve seat must be reconditioned f the valve seat is cracked the cylinder head must be replaced Cylinder Head Reconditioning NOTE Servicing the valve guides and valve seats requires special tools and a thorough knowledge of reconditioning techniques Follow the instructions provided in the cylinder head service tool kit Only use service kits designed specifically for ATV engines CAUTION Wear eye protection when performing cylinder head service Valve guide replacement will require heating of the cylinder head Wear gloves to prevent burns Valve Guide Removal Installation 1 Remove all carbon deposits from the combustion chamber valve seat and valve guide area before attempting to remove valve guides Ah CAUTION Carbon deposits are extremely abrasive and may damage the valve guide bore when guides are removed 2 Place new valve guides in a freezer for at least 15 minutes while heating cylinder head 3 Heat cylinder head in an oven or use a hot plate to bring cylinder head temperature to 212 F 100 C A 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 Wear the appropriate safety equipment for working with heated metal Follow the manufacturers instructions provided in the Valve Seat Reconditioning Kit Abrasive
34. e between the straight edge and the cylinder head surface If warpage exceeds the service limit replace the cylinder head Cylinder Head Disassembly A 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 Y 1 Using a valve spring compressor A compress the valve springs 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 progressively wound springs A 3 Push valve out keeping it in order for reassembly in the same guide 3 21 ENGINE 4 Measure free length of spring with a Vernier caliper Check spring for squareness Compare to specifications 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 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 use a dial indicator 3 Check end of va
35. e ee 3 29 PISTON ROD INSPECTION 0 000000 ea aaan pa EE KESE E Eaa aii 3 29 PISTON RING INSTALLED GAP oococcccccoc o 3 30 CRANKCASE DISASSEMBLY coco 3 30 STARTER DRIVE REMOVAL INSPECTION 0 00000000 eee ee 3 31 FLYWHEEL STATOR REMOVAL INSPECTION 0 000000 0005 3 31 CAM CHAIN TENSIONER BLADE 0 0 00000 c eee eee eee 3 32 ONE WAY VALVE REMOVAL 0 0 0000000 c eee ee 3 32 CRANKCASE SEPARATION 0 0002 e eee eee 3 33 3 1 ENGINE OIL PUMP REMOVAL INSPECTION 0 000000000 cee eee eee eee 3 33 OIL PUMP ASSEMBLY 6 ccc25 pecs ia bee bc ne ee ee ee Se 3 34 COUNTER BALANCER SHAFT REMOVAL INSPECTION 3 34 CRANKSHAFT REMOVAL INSPECTION 0 0 000 002 e eee eee eee 3 35 CRANKCASE BEARING INSPECTION 0 000 002 2 eee eee eee 3 36 PUMP SHAFT OIL SEAL WATER PUMP MECHANICAL SEAL REMOVAL 3 36 CRANKCASE INSPECTION 0 0 000000 c eee eee 3 36 BEARING INSTALLATION 0 0 00022 c eee 3 37 END PLAY INSPECTION ADJUSTMENT 0 0000000000 e eee eee 3 37 CRANKSHAFT END PLAY ADJUSTMENT 2 0 0 000000002020 3 37 COUNTER BALANCER SHAFT END PLAY ADJUSTMENT 3 38 OIL PUMP SHAFT END PLAY ADJUSTMENT 0 000 0020200005 3 39 ENGINE REASSEMBLY 2c 22o0050 cat rta rad e a 3 PUMP SHAFT OIL SEAL INSTALLATION 0 0 0000000000000 e eee 3 40 CRANKSH
36. ecompressor stuck Cylinder head gasket leak No valve clearance or incorrectly adjusted Cylinder or piston worn Piston rings worn leaking broken or sticking Bent valve or stuck valve Valve spring broken or weak Valve not seating properly carbon bent or accumulated on sealing surface e Rocker arm sticking Backfiring e ETC or speed limiter system malfunction Fouled spark plug or incorrect plug or plug gap e Carburetion faulty lean condition Exhaust system air leaks 3 54 e Ignition system faulty Spark plug cap cracked broken Ignition coil faulty Ignition or kill switch circuit faulty Ignition timing incorrect heared flywheel key Poor connections in ignition system e System wiring wet e Valve sticking Air leaks in intake e Lean condition Cooling System Overheating 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 radiator 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
37. ed wane and ww ae ess Ba hes Paes ere ee 3 14 CAM CHAIN TENSIONER ROCKER ARM CAMSHAFT REMOVAL 3 14 CAM CHAIN TENSIONER INSPECTION 0 0 000000002 eee eee eee 3 14 ROCKER ARM SHAFT INSPECTION 0 0 000 e eee eee 3 15 CAMSHAFT REMOVAL 0 0 000000 c eee eee 3 16 AUTOMATIC COMPRESSION RELEASE REMOVAL INSPECTION 3 17 AUTOMATIC COMPRESSION RELEASE INSTALLATION 2 3 18 CAMSHAFT INSPECTION 0000002 e eee 3 18 CYLINDER HEAD REMOVAL 0 000 002 c cece eee 3 19 CYLINDER HEAD EXPLODED VIEW EHS50PL 0 02005 3 20 CYLINDER HEAD INSPECTION 0 0 0 00000 e eee eee eee 3 21 CYLINDER HEAD WARP 0 000000 c ee eee 3 21 CYLINDER HEAD DISASSEMBLY 0 0000 c cece ee eee ee 3 21 VALVE INSPECTION a 2 004 2 dak2 en are eat di 3 22 COMBUSTION CHAMBER 0 0000 e cece 3 23 VALVE SEAT RECONDITIONING 0 0 000 0002 e eee eee eee eee 3 23 CYLINDER HEAD ASSEMBLY 0 0 00000 cece eee ee 3 26 VALVE SEALING TES Tis hissdir pro eared Pas le E eee eee eee 3 26 VALVE CLEARANCE ADJUSTMENT 0 000 0000 e eee eee eee ee 3 26 CYLINDER PISTON REMOVAL AND INSPECTION 0 2 005 3 27 PISTON REMOVAL 2000 dias tind Lary Pee es a ed Meda a 3 28 CYLINDER INSPEGTION iepure ci le etka a Seda eta 3 28 PISTON TO CYLINDER CLEARANCE 0 0 0000002 eee eee ee
38. el Reinstall friction plate TE The friction plate must be positioned with both end tabs of the friction spring opposite the ratchet pawl 10 11 Torque friction plate retaining bolt to 5 6 ft lbs 7 9 Nm Reinstall recoil housing using a new gasket Seal stator wire harness grommet with RTV silicone ENGINE TROUBLESHOOTING Spark Plug Fouling 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 adjuste 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 or breather system Improperly assembled air intake system Restricted engine breather system Oil contaminated with fuel Restricted oil tank vent Engine Engine Turns Over But Fails to Start No fuel Dirt in fuel line or filter Fuel will not pass through fuel valve Fuel pump inoperative restricted Tank vent plugged Carb st
39. emove handle from the rope and allow spring tension on recoil to relax NOTE The handle must seal tightly on the recoil housing to prevent water from entering 4 Remove center bolt from recoil friction plate A 5 6 Inspect plate for wear or damage Inspect plate friction spring for wear damage and proper tension The spring should fit tightly on friction plate Remove ratchet pawl with spring and inspect Replace spring or ratchet pawl if worn broken or damaged NOTE Long arm of spring engages reel Short end against pawl he 8 9 Hold reel firmly in housing Pull rope handle until 12 18 30 46cm 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 10 Unwind rope and inspect for cuts or abrasions 11 Inspect drive tab on hub return spring for damage To remove hub return spring hold outer coils in place with one hand and slowly remove spring one coil at a time from the inside out 12 Pull knot out of recoil reel Untie knot Remove rope from reel 3 51 ENGINE Recoil Assembly Be sure to wear a face shield and eye protection A CAUTION when performing this procedure
40. es Ill 6 Pump shaft oil seal can also be replaced at this time if necessary 7 The Water Pump Install Kit 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 One Way Valve Installation Install the one way valve plunger spring and plug using a new sealing washer One Way Valve Plug Torque 16 ft Ibs 22 Nm ENGINE Cam Chain Drive Sprocket Installation 1 Install the Woodruff key drive sprocket and slotted nut Tighten the nut to the specified torque ay Tighten Slotted Nut Torque 35 51 ft Ibs 47 69 Nm Tensioner Blade Installation 1 Install the tensioner blade and tighten the mounting bolt to specified torque Tensioner Blade Mounting Bolt Torque 6 ft Ibs 8 Nm 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 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 preve
41. for cracks or damage if a driver is used Reaming The Valve Guide 8 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 9 Clean guides thoroughly with hot soapy water and a nylon brush Rinse and dry with compressed air Apply clean engine oil to guides 10 Install pilot into valve guide 3 24 11 12 13 14 15 Apply cutting oil to valve seat and cutter a eN a Place 46 cutter on the pilot and make a light cut Inspect the cut area of the seat If the contact area is less than 75 of the circumference of the seat rotate the pilot 180 and make another light cut e 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 e If the contact area of the cutter is in the same place the valve guide is distorted from improper installation and must be replaced Be sure the cylinder head is at the proper temperature and replace the guide e If the contact area of the initial cut is greater than 75 continue to cut the seat until all pits are removed_and a new seat surface is evident NOTE Remove only the amount of material necessary to repair the seat surface To che
42. hreaded rod Hold the crankshaft and tighten the nut to draw the crankshaft into the main bearings until fully seated Loosen the nut and remove the threaded rod from the crankshaft If removal is difficult install two nuts on the end of the threaded rod and tighten against each other 3 Install the proper shim on the magneto end of the crankshaft 4 Place the balancer shaft in the PTO crankcase aligning the timing marks on the crankshaft and balancer gears Install the proper shim washer on the shaft 5 Inspect the oil pump sealing surface on the crankcase Apply a light film of engine oil to the surface and install the oil pump NOTE Do not use gasket sealer on the pump mating surfaces NOTE After engine is assembled and machine is readied for field operation oil pump MUST be primed Follow oil pump priming procedure Oil Pump Bolt Torque 6 ft Ibs 8 Nm 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 ENGINE Crankcase Assembly Water Pump Mechanical Seal Removal Engine Installed 1 Apply Crankcase Sealant PN 2871557 to the crankcase mating surfaces Be sure the alignment pins are in place 2 Set the crankcase in position carefully to avoid damaging Wate uller NPN SB 72105 the pump shaft seal and install the magneto end crankshaft installation tool foll
43. il 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 Cam Chain Tensioner Blade 1 Remove bolt securing tensioner blade to crankcase A 1 Remove cap bolt A sealing washer B spring C and one way valve D from PTO side crankcase 2 Inspect free length of spring and check coils for distortion One Way Valve Spring Free Length 2 Remove blade and inspect for cracks wear or damage Std 1 450 3 68 cm 3 Inspect valve for wear Check seat area for nicks or foreign material that may prevent proper sealing of valve 20 Pitch Section 3 Remove cam chain B Inspect chain for worn or missing rollers or damage Stretch chain tight on a flat surface and apply a 10 lb 4 53 kg load Measure length of a 20 pitch 3 32 ENGINE Crankcase Separation 3 Inspect drive gear teeth for cracks damage or excessive 1 Remove flange bolts 10 from magneto side crankcase 4 Remove three oil pump retaining bolts and pump evenly in a criss cross pattern 5 Inspect mating surface of crankcase and oil pump Check 2 Separate crankcase by tapping with a soft faced hammer in for nicks burrs or surface irregularities reinforced areas 3 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
44. iven sprocket bolts and remove chain and sprockets as an assembly 13 Refer to PVT System to remove outer clutch cover drive belt drive clutch driven clutch and inner cover 14 Starter motor Note ground cable location Mark positive cable mounting angle and remove cable 15 Remove transmission linkage rod s from gear selector and secure out of the way 16 Disconnect coolant temperature sensor wire 17 Remove engine to chassis ground cable 18 Remove all engine mount nuts and or engine mount plates 19 Remove engine through right side of frame ENGINE 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 removed 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 Clean clutch 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 e
45. ll the piston on the connecting rod with the arrow or mark 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 3 44 Cylinder Installation 7 Place the dowel pins in the crankcase and install a new cylinder base gasket 8 Position the Piston Support Block PN 2870390 A beneath the piston skirt to support the piston during cylinder installation 9 Apply clean engine oil to a ring compressor and install the compressor following manufacturers instructions 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 ENGINE 10 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 11 Remove the ring compressor and support block 12 Push the cylinder downward until fully seated on the base gasket 13 Apply a light film of oil to the threads and flange surface of the cylinder mounting bolts 14 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
46. lve stem for flaring pitting wear or damage A 4 Inspect split keeper groove for wear or flaring of the keeper 3 22 seat area B NOTE The valves cannot be re faced or end ground Valves must be replaced if worn bent or damaged Measure valve stem in several places Valve Stem Diameter Intake 2343 2348 5 950 5 965 mm 5 945 5 960 mm Exhaust 2341 2346 5 Measure diameter of valve stem with a micrometer in three places and in two different directions six measurements total Compare to specifications Valve Guide I D 2362 2367 6 0 6 012 mm 6 Measure valve guide inside diameter at the top middle and end of the guide using a small hole gauge and a micrometer Measure in two directions front to back and side to side 7 Subtract valve stem measurement to obtain stem to guide clearance NOTE Be sure to measure each guide and valve combination individually 8 Replace valve and or guide if clearance is excessive Compare to specifications NOTE If valve guides are replaced valve seats must be reconditioned Refer to Valve Seat Reconditioning for procedure ENGINE Combustion Chamber E s Clean all accumulated carbon deposits from combustion chamber and valve seat area with a soft wire brush Valve Seat Reconditioning Valve Seat Inspection Inspect valve seat in cylinder head for piling burnt spots roughness and an uneven surface lt any of th
47. nt rotation The tab must be positioned in the notch on the side of the piston as shown A 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 1 4 Install the second ring with the R mark facing up Position the end gap toward the rear intake side of the piston 5 Install the top ring chrome faced with the R mark facing up and the end gap facing forward toward the exhaust See ILL 1 6 Check to make sure the rings rotate freely in the groove when compressed Ring Profile A 3 43 ENGINE 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 Tang Outward 3 Install a new circlip on one side of the piston with the end gap facing up or down and tang outward A 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 Mag 5 Insta
48. ottom steel rail and a center expander section The top rail has propane torch a locating tab on the end which fits into a notch A in the upper TREE oil ring land of the piston Remove top compression ring 4 Remove the top rail first followed by the bottom rail 5 Remove the expander Cylinder Inspection 1 Remove all gasket material from the cylinder sealing surfaces CAUTION Do not apply heat to the piston rings The ring may lose radial tension Inspect the top of the cylinder for warpage using a straight ADE a piston ring pliers Carefully expand ring and lift it off edge and feeler gauge the piston 2 Cylinder Warp Limit A CAUTION 002 05 mm Do not expand the ring more than necessary to remove it from the piston or the ring may break 3 28 ENGINE 3 Inspect cylinder for wear scratches or damage 2 Subtract this measurement from the maximum cylinder 1 2 Down From Top of Cylinder measurement obtained in Step 5 above Piston to Cylinder Clearance Std 0006 0018 015 045 mm x Y M Piston O D Std 3 6204 3 6215 91 970 91 985 mm Piston Rod Inspection 1 2 Up From Bottom 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 f
49. ow instructions provided with the Replacement T Handle Crankshaft Water Pump Installation Kit PN 2871283 PN 2872106 Draw the crankcase halves together by tightening the nut on the tool and tapping lightly in the pump shaft area with This tool allows a technician to replace the mechanical a soft faced hammer to maintain alignment Continually water pump seal on EH50PL engines without removing check alignment of the cases during installation closing the the engine and splitting the cases gap equally until the surfaces are tightly seated 3 Remove the tool A CAUTION 4 Install the crankcase flange bolts and tighten in 3 steps following the pattern to specified torque Improper or careless use of this tool or procedure can result in a bent water pump shaft Pump shaft Crankcase Bolt Torque replacement requires engine removal and crankcase separation Use caution while performing this procedure 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 14 ft Ibs 19 Nm Crankcase Sealant PN 2871557 1 After the coolant has been drained remove the water pump cover impeller and the sealing washer Ill 1 Water Pump Mechanical Seal Installation Sealing Washer 5 Clean the seal cavity to remove all traces of old sealer 6 Place a new mechanical seal in the seal drive collar and install on
50. pecified range listed Crankshaft End Play 008 016 02 04 cm Counter Balancer Shaft End Play Adjustment _ _ a 7 Subtract the thickness of the straightedge from the measurement obtained in Step 4 and record Mag Case Depth 8 Add the readings recorded in Step 3 and Step 5 and record below Total Case Width 12 Make sure all bearings are firmly seated in the crankcase 13 Measure the width of the counter balancer shaft at the bearing seats with a dial caliper or micrometer and record reading 9 Measure the width of the crankshaft at the bearing seats with a micrometer or dial caliper and record Crankshaft Width 3 38 ENGINE 14 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 15 Measure the distance from the PTO crankcase mating surface to the bearing using the same method outlined in Step 1 2 and 3 16 Add the readings obtained in Step 3 and Step 4 17 Subtract the counter balancer shaft width measured in Step 2 from the figure obtained in Step 5 18 Subtract the thickness of the existing shim from the result of Step 6 to determine if a different shim is needed The result must be within the specified range listed at below Counter Balance Shaft End Play 008 016 02 04 cm Oil Pump Shaft End Play Adjustment 1
51. roga etn di rt iy eat ge et eee 3 53 COOLING SYSTEM sachs teste sa Seah Sika ails A a ti ia 3 54 3 2 ENGINE SPECIFICATIONS Special Tools Torque Specifications PART NUMBER TOOL DESCRIPTION Valve Seat Reconditionin TORQUE SPECIFICATIONS 2200634 Kit Fastener Size EH50PLE 2870390 Piston Support Block Ft Lbs Nm 2871043 Flywheel Puller Blind Plug Oil 1 8 PT 6 5 11 9 15 Nm Crankshaft Water Pump Pressure 28tpi epi lees Seal Install Kit Camshaft Sprocket 6mm 5 6 5 7 9 Nm 5131135 Water Pump Install Kit Camshaft Chain 6mm 9 6 5 7 9 Nm 2870569 Crankshaft Truing Stand Tensioner l ever Mity Vac Pressure Test Camshaft Chain 6mm 5 6 5 7 9 Nm 2870975 y a beaded PV 43527 Oll Filter Wrench Camshaft Chain Timm 14 19 20 25 Nm E Mer Arene Tensioner Cap A Carburetor Adaptor 8mm 12 14 16 20 Nm Engine Fastener Torque Patterns Crankcase 8mm 14 15 19 21 Nm Tighten cylinder head cylinder base and crankcase fasteners in Crankshaft Slotted Nut 28mm 35 51 47 69 Nm 3 steps following the sequence outlined Cam Chain Drive Sprocket Cylinder Base Bolts 10mm 45 49 61 67 Nm 6mm 6 8 9 11 Nm Cylinder Head Bolts 11mm Refer to Engine 6mm Assembly for torque procedure Drive Clutch Bolt 7 16 20 40 55 Nm Flywheel 16mm 58 72 78 98 Nm rial Harte Oil Delivery Pipe 12mm 11 15 15
52. rom bottom Piston Pin Bore 5 Record measurements If cylinder is tapered or out of round beyond 002 the cylinder must be re bored oversize or replaced Piston Pin Bore 9055 9057 23 0 23 006 mm Cylinder Taper ___ Limit 002 Max Cylinder Out of Round Limit 002 Max 1 Measure piston pin bore Standard Bore Size 3 6221 3 6228 92 00 92 012 mm Piston to Cylinder Clearance Piston k HA Piston Pin Measurement Locations Piston Pin O D 9053 9055 22 994 23 0 mm Piston Pin 1 Measure piston outside diameter at a point 40 mm down from the top of the piston at a right angle to the direction of the piston pin 3 29 ENGINE 2 Measure piston pin O D Replace piston and or piston pin 1f out of tolerance 3 Measure connecting rod small end ID Feeler Gauge Piston Ring to Groove Clearance Top Ring Std i ae 0031 040 080 mm 0 Second Ring sid oia 0028 030 070 mm Limit 0059 1 m 4 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 3 30 Piston Ring Installed Gap 1 Place each piston ring inside cylinder using piston to push ring squarely into place as shown at right Cylinder Piston Ring Installed Gap Std 0079 ohang Pomi 36 mm Limit ae 0mm Sec Std 007
53. se until hot to the touch Place the bearings in a freezer 1 Install the bearings so the numbers are visible 2 Drive or press new bearings into the crankcases using the proper driver CAUTION Press only on outer race of bearing to prevent bearing damage e 70 mm 2 755 driver For crankshaft main bearings 5 Subtract the thickness of the straightedge from the 28 mm 1 100 For pump shaft bearing measurement obtained in Step 2 and record 46 mm 1 810 For counter balancer bearings End Play Inspection Adjustment Before reassembling the crankcase the following steps should be performed to determine the amount of crankshaft counter balancer shaft and pump shaft end play Excessive end play may cause engine noise at idle and slow speeds Too little play will see load the bearings which may lead to premature bearing ailure Crankshaft End Play Adjustment 3 Make sure all bearings are firmly seated in the both Mag and PTO crankcase PTO Case Depth 3 37 ENGINE 6 Measure the distance from the Magneto crankcase mating 10 Subtract the Crankshaft Width measured in Step 7 from the surface to the main bearing using the same method and Total Case Width recorded in Step 6 and record below record Total End Play 11 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 s
54. stuck closed or not opening completely Possible loose or missing diverter inside radiator Temperature Too Low Thermostat stuck open Leak at Water Pump Weep Hole Faulty water pump mechanical seal coolant leak Faulty pump shaft oil seal oil leak
55. sure the dowel pins are in place and install the rocker shaft assembly 6 Apply a light film of engine oil to the threads of the bolts and tighten evenly Rocker Shaft Support Tower Bolt Torque 9 ft Ibs 12 Nm Rocker Shaft Locating Bolt Torque 6 ft Ibs 8 Nm 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 3 50 install the cover and bolts Rocker Cover Bolt Torque 6 ft Ibs 8 Nm 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 27 Nm ENGINE RECOIL Recoil Disassembly Inspection Replace any parts found to be worn or damaged Ne The recoil is under spring tension A face shield and CAUTION eye protection is required during this procedure Remove bolts and recoil from the engine Pull recoil rope if applicable so it is extended approximately 12 18 30 46cm 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 R
56. t The cooling system is under pressure and serious burns may result Allow the engine and cooling system to cool before servicing Radiator Thermostat Water Pump Cylinder Head Cylinder Upper Hose Radiator Filler Neck Lower Hose Ht ee Bottle System Pressure Test 1 Remove radiator cap cover located in storage box 2 Remove recovery bottle hose from coolant filler 3 Connect a Mity Vac PN 2870975 to radiator and pressurize system to 10 PSI 68 9 kpa The system must retain 10 lbs of pressure for five minutes or 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 The radiator cap relief pressure is 13 lbs 89 6 kpa Bottom Radiator Left Side View Radiator Front View 3 7 ENGINE RECOMMENDED COOLANT Use only ae quality antifreeze coolant mixed with distilled 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 comes pre mixed ready to
57. the pump shaft Copper or Alumiinin Sealing Washer 7 Screw the guide onto the end of the pump shaft fen E Le Oil 8 Install the washer and nut and tighten to draw seal into place Coolant Drain Y es Seal until fully seated A 9 Remove the guide adaptor using the additional nut as a jam nut if necessary Impeller Mechanical Seal 3 41 ENGINE 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 separated from the metal seal body Main Puller Body 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 Main puller body Position the split E 999 to opening on main puller body 4 Ensure that the split between the puller legs are fully supported by the main body of the tool III 4 Hex Socket Sa WS i Lip must grasp inside of mechanical seal 3 42 5 Tighten the hex socket screws on the puller legs sufficiently so the lip of the puller legs will grasp the mechanical seal TL 5 Main Puller Body 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 cas
58. ver shaft Stop Pin Spring in relaxed position If Camshaft Is Removed From Engine 3 Turn the camshaft until the actuator ball is in the lowest position and install the release lever shaft 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 3 18 Visually inspect each cam lobe for wear chafing or damage Thoroughly clean the cam shaft making sure the oil feed holes are not obstructed Cam Lobe Height Intake amp Exhaust Std 1 2884 102924 32 726 32 826 mm Limit 1 2766 32 426 mm ENGINE 3 Measure height of each cam lobe using a micrometer Cylinder Head Removal Compare to specifications Journal O D 1 Remove the two 6mm flange bolts A from cylinder head See next exploded view on next page 2 Loosen each of the four cylinder head bolts B evenly 1 8 turn e
59. xhaust gaskets Seal connections with high temp silicone sealant if required 2 Check to be sure all springs are in good condition Bleed Cooling System 1 Remove radiator cap and slowly add coolant to top of filler neck Fill coolant reservoir tank to full mark 3 Install radiator cap and squeeze coolant lines to force air out of system 4 Again remove radiator cap and slowly add coolant to top of fill neck 5 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 Engine Break In Period 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 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 Cylinder Hone Selection Honing Procedure Ah CAUTION 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
60. y Polaris Premium 4 Synthetic Engine Lubricant PN 2871281 Oil Pressure at 5500 RPM Engine Hot Standard 20 PSI Minimum 12 PSI Oil Pump Priming Procedure See Oil Pump Priming Procedure on page 2 25 Oil Flow EH50PL The following chart describes the flow of oil through the EHSOPL 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 eel side of the oil pump draws oil through the hos and into the crankcase oil gallery and then pumps the oil through another passage to the one way valve When the engine 1s off the one way valve closes to prevent oil in the tank from draining into the crankcase The oil is pumped through a delivery pipe to the oil filter If the oil filter is obstructed a bypass valve contained in the filter allows oil to bypass the filter element At this point the oil is diverted in two directions Oil is supplied to the camshaft through the left front cylinder stud and an oil passage in the head Oil enters the camshaft through the PTO L jou The camshaft journals cam lobes and rocker arms are ubricated 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
61. y TDC mark in timing inspection hole and alignment pin is directly in line with crankshaft to camshaft centerline Refer to illustration Apply Crankcase Sealant PN 2871557 to the camshaft end cap and install using a new O Ring Check all cam timing marks to verify proper cam timing and install the cam chain tensioner body with a new gasket After tensioner installation rotate engine at least two revolutions and re check marks timing 3 47 ENGINE CAMSHAFT TIMING Dots Crankshaft to Camshaft Centreline WAM Sprocket Alignment Pin Single TDC Mark Aligned TDC Mark ey QH E on ig Cee E Rotation aoe Bana Do Not Use Advance Marks 3 48 ENGINE Cam Chain Tensioner Installation 1 Release the ratchet pawl A and push the tensioner plunger B all the way into the tensioner body A i Install the tensioner body with anew gasket and tighten the bolts Tensioner Bolt Torque 6 ft Ibs 8 Nm 3 Install the spring new sealing washer and tensioner plug Tensioner Plug Torque 17 ft Ibs 23 Nm 4 Slowly rotate engine two to three revolutions and re check cam timing 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
62. y result if the camshaft is not properly timed to the crankshaft 3 45 ENGINE IMPORTANT CAMSHAFT TIMING NOTE In order to 4 Loop the cam chain on the cam sprocket with the dots on time the camshaft to the crankshaft the piston must be i i t vi h precisely located at Top Dead Center TDG the sprocket facing outward and the alignment pin notc facing directly upward Camshaft Timing l Apply Polaris Premium Starter Drive Grease PN position of the cam sprocket alignment pin When the cam 2871460 to the camshaft main journals and cam lobes is positioned properly the cam sprocket alignment pin A Lubricate automatic compression release mechanism with is directly in line with the crankshaft camshaft centerline clean engine oil B 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 illustration Single TDC Mark Aligned 3 46 6 10 ENGINE Install the sprocket on the camshaft Apply LoctiteTM 242 PN 2871949 to the cam sprocket bolts and torque to specification Cam Sprocket Bolt Torque 6 ft Ibs 8 Nm Single TDC Mark Aligned Verif

2008 Sportsman 500 Service Manual Chapter 3

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