Husqvarna 345FR, Workshop Manual

Page: 50 / 66

6
48
Cylinder and piston
Cause:
• Air fi lter damaged or missing.
• Parts from the carburettor or intake
system have come loose and entered
the engine.
Action:
Fit a new air fi lter.
Regular service and inspection.
Larger, harder particles that enter the engine cause serious damage to the under-
side of the piston skirt.
Cause:
• Faulty air fi lter. Small dust particles
pass through the fi lter.
• The
fi
lter is worn out due to too
much cleaning, whereby small holes
have appeared in the material.
• Unsuitable
fi
lter maintenance, such
as wrong method or wrong cleaning
agent. Flock material becomes loose
and holes appear.
• Air
fi
lter incorrectly
fi
tted.
• Air fi lter damaged or missing.
Action:
Fit a fi ner grade fi lter.
Check the
fi
lter carefully for holes and
damage after cleaning. Replace the
fi
lter
if necessary.
Clean more carefully and use the right
cleaning agent (such as tepid soapy
water).
Change the
fi
lter.
Fit the fi lter correctly.
Fit a new air
fi
lter.
Larger, softer particles that penetrate into the engine cause damage to the piston
skirt under the piston ring as the illustration shows.
Cause:
• Air fi lter incorrectly fi tted.
• Air
fi
lter damaged or missing.
Action:
Fit the air fi lter correctly.
Fit a new air
fi
lter.
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
fi rmly 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.
The piston scored and worn from the piston
ring down on the inlet side.
Extensive damage to the lower part of the
piston’s inlet side.