Service manual

Page 40 of 151

Special Service Tools

• Valve reamer: 5.0mm

• Valve guide driver: 5.0mm

• Valve spring compressor

6-3 Troubleshooting

Engine performance can be affected by problems in the top end. The trouble usually can be

determined or by performing cylinder compression test and judging the abnormal noise

generated.

Low compression pressure

1. Valve

• Improper valve adjustment

• Burnt or bent valve

• Improper valve timing

• Valve spring damage

• Valve carbon deposit

2. Cylinder head

• Cylinder head gasket leaking or damage

• Tilted or cracked cylinder

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 worn out or damaged

• Chain worn out or loose

• Auto-tensioner worn out or damaged

• Camshaft sprocket

• Rocker arm or rocker arm shaft worn out