Troubleshooting - KYMCO Bet & Win 125 User Manual

6
. CYLINDER HEAD/VALVES

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
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
Compression too high
• Excessive carbon build-up in combustion
chamber
6-3
White smoke from exhaust muffler
• Worn valve stem or valve guide
• Damaged valve stem oil seal
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
Bet & Win 125/150