- Remove cam gear cover -
- Remove the fanwheel -
- Remove lower half of crankcase
•
Lift crankshaft and pull piston out
of cylinder at the same time.
- Inspect cylinder running face,
replace cylinder if necessary -
•
Remove the oil seals (1).
•
Inspect the piston (2), ball
bearing (3) and oil splash
plate (4).
- If one of these parts is damaged,
the complete crankshaft must be
replaced.
•
Before installing the crankshaft,
check oilway for blockages
and blow clear with compressed
air if necessary.
- Coat piston, piston rings and oil
scraper ring with oil.
- Fit piston ring so that their gaps
are offset 120 degrees.
Important: Ring gaps must not be
in line with piston pin bore.
•
Rotate cam gear so that the
marks (1) are in alignment.
- Carefully push the piston into the
cylinder.
Note: The piston rings and the oil
scraper ring are compressed as
they are eased into the tapered
cylinder.
•
Turn the crankshaft so that the
slot (2) points towards the cam
gear.
•
Continue pushing piston into
cylinder and make sure that the
marked tooth (3) lines up with
the slot.
- Fit new oil seals with the open
side facing the crankshaft and
push crankshaft fully home.
Note: Annular rib (1) must engage
groove (2).
Assemble all other parts in
the reverse sequence.
FS 25-4, 65-4
17
