Troubleshooting - KYMCO AHG5 Service Manual

6. CYLINDER HEAD/ VALVE
DT X360

2.5. 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
Compression too low
White smoke from exhaust muffler
Worn valve stem or valve guide
Damaged valve stem oil seal
Compression too low
Incorrect valve clearance adjustment
Burned or bend valves
Incorrect valve timing
Broken valve spring
Poor valve and seat contact
Leaking cylinder head gasket
Warped or cracked cylinder head
Poorly installed spark plug
Abnormal noise
Incorrect valve clearance adjustment
Sticking valve or broken valve spring
Damaged or worn camshaft
Worn cam chain tensioner
Worn camshaft and rocker arm
Compression too high
Excessive carbon build-up in combustion chamber or on piston head.
White smoke from exhaust muffler
Worn valve stem or valve guide
Damaged valve stem oil seal
Excessive smoke from exhaust muffler
Worn or damaged piston rings
Worn or damaged cylinder and piston
6-5