Piston Rings - Stihl FS 94 Instruction Manual

1
: Slide the assembly drift (1)
1130 893 4700, small diameter
first, through the side of the
piston opposite the snap ring
groove and the small end (needle
cage) and line up the piston.
– Lubricate the piston pin with oil.
: Fit the piston pin (2) on the
assembly drift (1) and slide it into
the piston.
– Prepare snap ring for installation
with installing tool
5910 890 2208.
1
Fit the snap ring (1) so that its gap
(arrow) points up.
Series 4149 Powerhead
2
: Installing tool
5910 890 2208 with the sleeve's
taper against the piston boss,
hold the piston steady, center the
tool shank exactly and press
home until the snap ring slips into
the groove.
Make sure the tool is held square on
the piston pin axis.
– Install the cylinder, b 5.5
– Reassemble all other parts in the
reverse sequence.
5.8

Piston Rings

– Remove the piston, b 5.7
– Remove the piston rings from the
piston.
– Use a broken piece of old piston
ring to scrape the grooves clean.
: Install the new piston rings in the
grooves so that the radii face
upward (arrows).
– Carefully fit the piston rings over
the piston – they might otherwise
break.
: Install the piston rings so that the
radii at the ring gap meet at the
fixing pins in the piston grooves
(arrows).
: Check correct installed position
of the piston rings (arrows).
– Install the piston, b 5.7
– Reassemble all other parts in the
reverse sequence.
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