6. CYLINDER HEAD/CYLINDER/PISTON
6
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CYLINDER HEAD/CYLINDER/PISTON
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SERVICE INFORMATION........................................................ 6-3
TROUBLESHOOTING.............................................................. 6-3
CYLINDER HEAD.................................................................... 6-4
CYLINDER/PISTON................................................................. 6-8
6. CYLINDER HEAD/CYLINDER/PISTON
Torque: 1.1_ 1.7kg-m (cold)
6. CYLINDER HEAD/CYLINDER/PISTON
Torque: 1.1_ 1.7kg-m
(cold)
6. CYLINDER HEAD/CYLINDER/PISTON
SERVICE INFORMATION
GENERAL INSTRUCTIONS
• The cylinder head, cylinder and piston can be serviced with the engine installed in the frame.
• Before disassembly, clean the engine to prevent dust from entering the engine.
• Remove all gasket material from the mating surfaces.
• Do not use a driver to pry between the cylinder and cylinder head, cylinder and crankcase.
• Do not damage the cylinder inside and the piston surface.
• After disassembly, clean the removed parts before inspection. When assembling, apply the
specified engine oil to movable parts.
Piston O.D.(5mm from bottom of piston
Cylinder-to- piston clearance
Piston-to-piston pin clearance
Piston ring end gap (top/second)
Connecting rod small end I.D.
TORQUE VALUES
Cylinder head bolt 1.5_ 1.7kg-m
Exhaust muffler joint lock nut 1.0_ 1.4kg-m
Exhaust muffler lock bolt 3.0_ 3.6kg-m
Spark plug 1.1_ 1.7kg-m
TROUBLESHOOTING
Compression too low, hard starting
or poor performance at low speed Abnormal noisy piston
• Leaking cylinder head gasket • Worn cylinder and piston
• Loose spark plug • Worn piston pin or piston pin hole
• Worn, stuck or broken piston and piston rings • Worn connecting rod small end bearing
• Worn or damaged cylinder and piston
Compression too high, overheating
or knocking Abnormal noisy piston rings
• Excessive carbon build-up in cylinder head • Worn, stuck or broken piston rings
or on piston head • Worn or damaged cylinder