Operators Manual

English - 51
Repair instructions
Foreign objects
Everything other than clean air and pure fuel that
enters the engine’s inlet port causes some type
of abnormal wear or damage to the cylinder and
piston.
This type of increased wear shows on the piston’s
inlet side starting at the lower edge of the piston
skirt.
The damage is caused by badly filtered air that
passes through the carburettor and into the engine
Inlet side.
Particles of dust and dirt from carbon-like deposits
on the top of the piston and in the piston ring
groove. The piston ring sits firmly in the groove.
Piston material has been worn away.
The lower part of the piston skirt is thinner on the
inlet side than on the exhaust side.
Cause: Action:
Faulty air filter. Small
dust particles pass
through the filter.
Replace to a correct
and a new filter.
The filter is worn out
due to too much clean-
ing, whereby small
holes have appeared in
the material.
Check the filter care-
fully for holes and
damage after cleaning.
Replace the filter if
necessary.
Unsuitable filter mainte-
nance, such as wrong
method or wrong clean-
ing agent. Flock mate-
rial becomes loose and
holes appear.
Clean more care-
fully and use the right
cleaning agent (such
as tepid soapy water).
Change the filter.
Air filter incorrectly
fitted.
Fit the filter correctly.
Air filter damaged or
missing
fit a new air filter
Larger, softer particles that penetrate into the
engine cause damage to the piston skirt under the
piston ring as the illustration shows.
Cause: Action:
Air filter incorrectly
fitted.
Fit the air filter correctly.
Air filter damaged or
missing.
Fit a new air filter.