DAELIM NS125III Service Manual page 95

Cylinder Head/Valve
Tools
Valve guide reamer
Valve guide driver
Valve spring compressor
Valve seat cutter
Seat Cutter IN 37 (21.5mm)
EX 37 (18.5mm)
IN 45 (22mm)
EX 45 (22mm)
IN 55 (20mm)
EX 55 (20mm)
Troubleshooting
Cylinder head operation problem can be diagnosed,
in general, by a compression test, or by checking
noises on the top of the engine.
Low compression or uneven compression
Valves
- Faulty hydraulic tappet
- Burned or bent valves
- Incorrect valve timing
- Broken valve spring
Cylinder head
- Leaking or damaged head gasket
- Warped or cracked cylinder head
Cylinder and piston (Refer to Section 10)
9-2
Compression too high
- Excessive carbon build-up on piston head or
combustion chamber
Excessive noise
Faulty hydraulic valve tappet system
- Low engine oil level
- Contaminated oil
- Low oil pressure
- Damaged hydraulic tappet
Sticking valve or broken valve spring
Damaged or worn camshaft
Loose or worn cam chain
Worn or damaged cam chain tensioner
Worn cam sprocket teeth