Operation Manual

6. Cylinder Head / Valve
6-3
Troubleshooting
Engine performance will be affected by troubles on engine top end. The troubles usually can be
determinate or by performing cylinder compression test and judging the abnormal noise generated.
Rough Idle
Low compression pressure
Low compression pressure
1. Valve
y Improper valve adjustment
y Burnt or bended valve
y Improper valve timing
y Valve spring damaged
y Valve carbon
y Poor sealing on valve seat
y Improper spark plug installation
2. Cylinder head
y Cylinder head gasket leaking or damage
y Tilt or crack cylinder surface
3. Piston
y Piston ring worn out
High compression pressure
y Too much carbon deposit on combustion chamber or piston head
Noise
y Improper valve clearance adjustment
y Burnt valve or damaged valve spring
y Camshaft wear out or damage
y Cam chain wear out or looseness
y Auto-tensioner wear out or damage of cam chain
y Camshaft sprocket wear out
y Rocker arm or rocker arm shaft wear out
White smoke
y Valve guide or valve stem wear out
y Valve stem seal wear out
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