91
Cylinder and piston
7
Reasons:
● Defective air filter. Small dust particles
pass through the filter.
● The filter is worn out as a result of
overcleaning, whereby small holes
have been made in the filter material.
● Insufficient maintenance of the filter,
e.g. the use of incorrect method or
incorrect solvent. Flocculation mate-
rial releases and holes are made in
the air filter.
● The air filter is incorrectly fitted.
● The air filter is damaged or missing.
Procedure:
Fit a fine-mesh filter.
Check the filter carefully for holes and
damage each time it is cleaned. Change
the filter if necessary.
Carefully clean and use the correct sol-
vent (e.g. lukewarm soapy water).
Change filter.
Fit the filter correctly.
Fit a new air filter.
Inlet side.
Dust and dirt particles from carbon deposits on
the head of the piston and in the piston ring
groove. The piston ring is stuck in the groove.
Piston material is worn off.
The lower part of the piston skirt on the inlet side
is thinner than on the exhaust side.
Large, softer particles which have entered the engine result in damage to the piston
skirt under the piston ring as shown in the illustration.
Reasons:
● The air filter is incorrectly fitted.
● The air filter is damaged or missing.
Procedure:
Fit the air filter correctly.
Fit a new air filter.
The piston is worn and scratched from the piston
ring and downwards on the inlet side.
Large, hard particles which enter the engine result in more severe damage to the lower
part of the piston skirt.
Reasons:
● The air filter is damaged or missing.
● Parts from the carburettor or inlet
system have released and entered
the engine.
Procedure:
Fit a new air filter.
Regular service and control.
Severe damages to the lower part of the piston on
the inlet side.