Piston Rings - Stihl MS 231 Manual

: Apply the installing tool
5910 890 2210 with the sleeve
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.
– Inspect the piston rings and
replace if necessary, b 6.9
– Install the crankshaft and new oil
seals, b 6.5
– Install the crankshaft, b 6.6
– Install the engine, b 6.5
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6.9

Piston Rings

– Remove the piston, b 6.8
– Remove the piston rings from the
piston.
: Use a piece of old piston ring to
scrape the grooves (arrows)
clean.
: Position the new piston rings 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 6.8
– Reassemble all other parts in the
reverse sequence.
MS 231, MS 231 C, MS 251, MS 251 C