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8. CYLINDER/PISTON

8-0

MX’er SYSTEM

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CYLINDER /PISTON

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SERVICE INFORMATION -------------------------------------------- 8- 2

TROUBLESHOOTING ------------------------------------------------- 8- 2

CYLINDER REMOVAL------------------------------------------------ 8- 4

PISTON REMOVAL ---------------------------------------------------- 8- 4

PISTON INSTALLATION --------------------------------------------- 8- 8

CYLINDER INSTALLATION----------------------------------------- 8- 8

Summary of content (9 pages)

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8. CYLINDER/PISTON MX’er SYSTEM SERVICE INFORMATION GENERAL INSTRUCTIONS • The cylinder and piston can be serviced with the engine installed in the frame. • After disassembly, clean the removed parts and dry them with compressed air before inspection. TROUBLESHOOTING • When hard starting or poor performance at low speed occurs, check the crankcase breather for white smoke. If white smoke is found, it means that the piston rings are worn, stuck or broken.
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8. CYLINDER/PISTON MX’er SYSTEM SPECIFICATIONS Mx’er 150 Standard (mm) Service Limit (mm) I.D. 62.03_ 62.045 æ Warpage æ 0.05 Cylinder Cylindricity æ 0.05 True roundness æ 0.05 0.015_ 0.055 0.09 Ring-to-groove Top clearance Second 0.015_ 0.055 0.09 Top 0.10_ 0.25 0.5 Ring end gap Second 0.10_ 0.25 0.5 Piston, piston ring Oil side rail 0.2_ 0.7 æ Piston O.D. 61.96_ 62 æ Piston O.D. measuring position 5mm from bottom of skirt æ . Piston-to-cylinder clearance 0.010_ 0.040 0.1 Piston pin hole I.D. 15.002_ 15.
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8. CYLINDER/PISTON CYLINDER REMOVAL MX’er SYSTEM Bolt Turn the cam chain tension screw clockwise to tighten it. Remove the two bolts on the cam chain tension. Cylinder Remove the cylinder head. Remove the cam chain guide. Remove the cylinder base bolts. Remove the cylinder . Remove the cylinder gasket and dowel pins. Clean any gasket material from the cylinder surface. Dowel Pins PISTON REMOVAL Piston Remove the piston pin clip.
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8. CYLINDER/PISTON Inspect the piston, piston pin and piston rings. Remove the piston rings. ＊ Take care not to damage or break the piston rings during removal. Clean carbon deposits from the piston ring grooves. Install the piston rings onto the piston and measure the piston ring-to-groove clearance. Service Limits: Top: 0.09mm replace if over 2nd: 0.09mm replace if over Remove the piston rings and insert each piston ring into the cylinder bottom.
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8. CYLINDER/PISTON MX’er SYSTEM Measure the piston pin O.D. Service Limit: 14.96mm replace if below Measure the piston O.D. ＊ Take measurement at 5mm from the bottom and 90° to the piston pin hole. Piston O.D.: 61.96_ 62mm (MX’er 150) Piston O.D.: 56.46_ 56.5mm (MX’er 125) Measure the piston-to-piston pin clearance. Service Limit: 0.02mm replace if over CYLINDER INSPECTION Inspect the cylinder bore for wear or damage. Measure the cylinder I.D.
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. CYLINDER/PISTON MX’er SYSTEM Inspect the top of the cylinder for warpage. Service Limit: 0.05mm repair or replace if over Measure the connecting rod small end I.D. Service Limit: 15.06mm replace if over PISTON RING INSTALLATION Install the piston rings onto the piston. Apply engine oil to each piston ring. ＊• Be careful not to damage or break the piston and piston rings. • All rings should be installed with the markings facing up.
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8. CYLINDER/PISTON MX’er SYSTEM PISTON INSTALLATION Remove any gasket material from the crankcase surface. ＊ Be careful not to drop foreign matters into the crankcase. Piston Install the piston, piston pin and a new piston pin clip. ＊• Position the piston “IN” mark on the intake valve side. • Place a clean shop towel in the crankcase to keep the piston pin clip from falling into the crankcase. Piston Pin Clip CYLINDER INSTALLATION Install the dowel pins and a new cylinder gasket on the crankcase.