Piston - Stihl MS 661 Manual

Installing
– Heat area of bearing seat to
about 160°C (320°F).
: Position the ball bearing so that
its open side (balls visible) faces
the inside of the crankcase and
then press it home as far as stop.
This operation must be carried out
quickly because the bearing
absorbs heat and begins to expand.
– Check that the bearing is properly
seated. If necessary, use
press arbor 1120 893 7200 to
press the bearing fully home.
Clutch side of crankcase
The oil seal is seated in the ball
bearing and does not need to be
removed separately.
– Check and clean the crankcase
or replace if necessary.
36
– If this half of the crankcase is in
order, install a new ball bearing.
– Heat area of bearing seat to
about 160°C (320°F).
When this temperature is reached,
the ball bearing drops out together
with the oil seal – if necessary, use
press sleeve 1129 893 2400 to
press out the ball bearing through
the oil pump.
Installing
As the clutch side of the crankcase
has no stop in its bearing seat, the
mounted oil pump is used as a stop.
– Heat area of bearing seat to
about 160°C (320°F).
: Position the ball bearing so that
the oil seal's seat faces the oil
pump and then press home the
ball bearing until it butts against
the oil pump.
This operation must be carried out
quickly because the bearing
absorbs heat and begins to expand.
– Check that ball bearing is
properly seated. If necessary,
use press arbor 1144 893 2400
to carefully press the bearing fully
home until it butts against the oil
pump
If the oil has been removed for any
reason, carefully press home the
ball bearing with the press arbor
until its outer race projects 0.8 mm
from the bearing seat at the clutch
side.
0,8 mm
– Remove the oil pump, b 12.3
– Install the crankshaft, b 6.6
– Install the oil seals, b 6.3
– Reassemble all other parts in the
reverse sequence.
6.7

Piston

Before removing the cylinder,
decide whether or not the
crankshaft has to be removed as
well, b 6.6
– Remove the cylinder, b 6.5
It is not necessary to remove the
snap ring at the clutch side.
: Pry hookless snap ring out of
boss at ignition side – apply tool
to recess (arrow).
MS 661, MS 661 C-M