Troubleshooting - KYMCO People Service Manual

6. CYLINDER HEAD/VALVES

TROUBLESHOOTING

x The poor cylinder head operation can be diagnosed by a compression test or by tracing engine
top-end noises.
Poor performance at idle speed
x Compression too low
Compression too low
x Incorrect valve clearance adjustment
x Burned or bend valves
x Incorrect valve timing
x Broken valve spring
x Poor valve and seat contact
x Leaking cylinder head gasket
x Warped or cracked cylinder head
x Poorly installed spark plug
Compression too high
x Excessive carbon build-up in combustion
chamber
6-3
PEOPLE/PEOPLE S 250
White smoke from exhaust muffler
x Worn valve stem or valve guide
x Damaged valve stem oil seal
Abnormal noise
x Incorrect valve clearance adjustment
x Sticking valve or broken valve spring
x Damaged or worn camshaft
x Worn cam chain tensioner
x Worn camshaft and rocker arm