Operators Manual

50 - English
Repair instructions
Piston ring guide pin vibrated loose
A too high engine speed can cause the ends of the
piston ring to hammer against the guide pin when
the piston ring moves in its groove. The intensive
hammering can drive out the pin through the top
of the piston causing serious damage also to the
cylinder.
Damage caused by gudgeon pin circlips
A too high engine speed can cause the gudgeon
pin circlips to vibrate. The circlips are drawn out of
their grooves due to the vibrations, which in turn
reduces the circlips’ tensioning power. The rings
can then become loose and damage the piston.
Bearing failure
Failure of the crankshaft bearing or on the
connecting rod bearing is usually caused by a too
high engine speed, resulting in the bearing being
overloaded or overheating. This in turn can cause
the bearing rollers or ball to glide instead of rotate,
which can cause the roller or ball retainer to break.
The broken debris can be trapped between the
piston and cylinder wall, damaging the piston skirt.
Debris can also pass up through the cylinder’s
transfer channels and cause damage to the top
and sides of the piston as well as to the cylinder’s
combustion chamber.