Husqvarna 525BX Workshop Manual page 53

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:
Faulty air filter. Small
dust particles pass
through the filter.
The filter is worn out
due to too much clean-
ing, whereby small
holes have appeared in
the material.
Unsuitable filter mainte-
nance, such as wrong
method or wrong clean-
ing agent. Flock mate-
rial becomes loose and
holes appear.
Air filter incorrectly
fitted.
Air filter damaged or
missing.
Larger, softer particles that penetrate into the
engine cause damage to the piston skirt under the
piston ring as the illustration shows.
Cause:
Air filter incorrectly
fitted.
Air filter damaged or
missing.
Action:
Replace filter to the
proper one.
Check the filter care-
fully for holes and
damage after cleaning.
Replace the filter if
necessary.
Clean more care-
fully and use the right
cleaning agent (such
as tepid soapy water).
Change the filter.
Fit the filter correctly.
Fit a new air filter.
Action:
Fit the air filter correctly.
Fit a new air filter.
Repair instructions
53
English -