Cylinder Head/Valves Troubleshooting - DAELIM HISTORY 125 Service Manual

CYLINDER HEAD / VALVES
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° (22.0mm)
EX 45° (22.0mm)
IN 55° (20.0mm)
EX 55° (20.0mm)
TROUBLESHOOTING
Enging top-end problems useally affect engine performance. These can be diagnosed by a compression or leak down test,
or by tracing noises to the top-end with a sounding rod or stethoscope.
Low comperssion
● Valves
-Incorrect valve adjustment (see section 3)
-Burned or bent valves
-Incorrect valve timing
-Broken valve spring
-Uneven valve seating
● Cylinder head
-Leaking or damage head gasket
-Warped or cracked cylinder head
● Cylinder, piston (see section 10)
Excessive white smoke
● Worn valve guide or valve stem
● Damaged valve stem seal
● Worn or damaged piston ring
9-2
Rough idle
● Low cylinder compression
Compression too high
● Excessive carbon build-up on piston or combustion
chamber
Excessive noise
● Incorrect valve adjustment
● Sticking valve or broken valve spring
● Damaged or worn camshaft
● Worn rocker arm and / or shaft
● Loose or worn cam chain
● Worn or damaged cam chain tensioner
● Damaged cylinder head gasket
● Incorrect spark plug installation