TROUBLESHOOTING

Note: This section is by no means complete, it is simply designed as a starting point.

PISTON AND CYLINDER ISSUES

LACK OF POWER

Improper assembly, cam timing or tuning
Incompatible modifications (component conflict)
Improper jetting – too rich or too lean

EXCESSIVE SMOKING AND OIL CONSUMPTION

Cylinder finish too coarse
Excessive piston/cylinder wall clearance
Rings improperly installed (upside-down, or oil ring overlapped)
Broken Ring

BROKEN RINGS

Insufficient ring end-gap
Mishandling or breakage during installation
Excessive piston/cylinder wall clearance
Improper tuning – causing detonation
Over-revving

PISTON "KNOCKING"

Excessive piston/cylinder wall clearance
Broken piston
Piston striking valves, flyweights, head or spark plug
Worn/loose rod

PISTON SEIZURE

Insufficient piston/cylinder wall clearance
Over-revving
Engine overheating due to any of the following:
Lean fuel mixture
Lack of oil
Low octane fuel
Improper ignition timing
Broken rings
Incompatible modifications (component conflict)

Always check the easiest and most basic things before jumping to complex conclusions. Sometimes, a rider will blame a dead bike on a piston seizure when all it needs is some fuel.