KYMCO Downtown 200i, Service Manual, Page: 61 / 230

6. CYLINDER HEAD/VALVES
6-3
DOWNTOWN 200i
TROUBLESHOOTING
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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
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Worn valve stem or valve guide
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Damaged valve stem oil seal
Compression too low
•
Incorrect valve clearance adjustment Abnormal noise
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Burned or bend valves
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Incorrect valve clearance adjustment
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Incorrect valve timing
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Sticking valve or broken valve spring
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Broken valve spring
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Damaged or worn camshaft
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Poor valve and seat contact
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Worn cam chain tensioner
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Leaking cylinder head gasket
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Worn camshaft and rocker arm
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Warped or cracked cylinder head
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Poorly installed spark plug
Compression too high
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Excessive carbon build-up in combustion
chamber