KYMCO Super 8 50, Service Manual, Page: 85 / 185

7
. CYLINDER HEAD/VALVES
7-2
Super 8 50
TORQUE VALUES
Cylinder head nut 1.8~2.2kgf-m Apply engine oil to threads
Valve clearance adjusting nut 0.7~1.1kgf-m Apply engine oil to threads
SPECIAL TOOLS
Valve spring compressor
TROUBLESHOOTING

The poor cylinder head operation can be diagnosed by a compression test or by tracing engine
top-end noises.
Poor performance at idle speed White smoke from exhaust muffler

Compression too low

Worn valve stem or valve guide

Damaged valve stem seal
Compression too low

Incorrect valve clearance adjustment Abnormal noise

Burned or bend valves

Incorrect valve clearance adjustment

Incorrect valve timing

Sticking valve or broken valve spring

Broken valve spring

Damaged or worn camshaft

Poor valve and seat contact

Worn cam chain guide

Leaking cylinder head gasket

Worn camshaft and rocker arm

Warped or cracked cylinder head

Poorly installed spark plug
Compression too high

Excessive carbon build-up in combustion
chamber