Troubleshooting - Sym Mio 50 Service Manual

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
Improper valve adjustment
Burnt or bended valve
Improper valve timing
Valve spring damaged
Valve carbon
Poor sealing on valve seat
Improper spark plug installation
2. Cylinder head
Cylinder head gasket leaking or damage
Tilt or crack cylinder surface
3. Piston
Piston ring worn out
High compression pressure
Too much carbon deposit on combustion chamber or piston head
Noise
Improper valve clearance adjustment
Burnt valve or damaged valve spring
Camshaft wear out or damage
Cam chain wear out or looseness
Auto-tensioner wear out or damage of cam chain
Camshaft sprocket wear out
Rocker arm or rocker arm shaft wear out
White smoke
Valve guide or valve stem wear out
Valve stem seal wear out
To this chapter contents
6. Cylinder Head / Valve
6-3