Honda SH125 Manual page 187

CY LINDER/PISTON
TROUBLESHOOTING
Compression too
low,
hard starting or poor performance at low speed
Worn, stuck or broken piston ring
Worn or damaged cylinder and piston
Cylinder headhalve problem (page 8-6)
Compression too high, overheating or knocking
Excessive carbon build-up on piston head or on combustion chamber
Excessive smoke
Worn cylinder, piston or piston ring
Improper installation of piston rings
Scored or scratched piston or cylinder wall
Cylinder headhalve problem (page 8-6)
Abnormal noise
Worn piston pin or piston pin hole
Worn connecting rod small end
Worn cylinder, piston or piston rings
Piston ring stickinglscuffing, bearing damage
Clogged oil gallery or oil strainer screen
Internal oil leak
Use of poor quality engine oil
9-4