DAELIM NS125DLX Service Manual page 86

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