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)
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
9-2
Summary of Contents for NS125DLX
Page 1: ...SERVICE MANUAL...
Page 4: ...Service Information 1 2 Identification Numbers Frame serial number Engine serial number...
Page 22: ...MEMO...
Page 43: ...MEMO...
Page 44: ...Fuel System 5 0 Fuel tank Fuel strainer Fuel pump Carburetor...
Page 54: ...MEMO...
Page 58: ...L Crank Case Cover Kick Starter Continuously Variable Transmission 7 0 L crank case cover...
Page 76: ...Generator Starter Clutch 8 0...
Page 107: ...MEMO...
Page 108: ...Transmission Crankshaft Crank Case 11 0 R Crank Case Crankshaft L Crank Case...
Page 154: ...MEMO...
Page 168: ...MEMO...
Page 172: ...MEMO...
Page 180: ...MEMO...
Page 182: ...MEMO...
Page 190: ...2001 4 PRINTED 2001 4 PUBLICATION SERVICE MANUAL NO COPY...