Checking/Measuring The Piston - Husqvarna FS 450 2019 Repair Manual

17 ENGINE
17.4.18
198

Checking/measuring the piston

e -' ­
+
400995-10
310043-10
Use the special tool to measure clearance
rings in the piston ring groove.
Guideline
Piston ring - groove clear­
ance
I Feeler gauge (59029041100)
f)
If clearance larger than the specified value:
Change the piston and piston rings.
Check/measure the cylinder.
-
Check the piston bearing surface for damage.
If the piston bearing surface is damaged:
Replace the piston and, if necessary, the cylinder.
-
Check that the piston rings move easily in the piston ring
grooves.
If the piston ring is stiff:
Clean the piston ring groove.
Tip
An old piston ring can be used to clean the
piston ring groove.
-
Check the piston rings for damage.
If the piston ring is damaged:
Change the piston ring.
• Info
I
Mount the piston ring with the marking facing
upward.
-
Check the piston pins for discoloration or signs of wear.
If the piston pin shows severe discoloration/signs of wear:
Change the piston pin.
Place the piston pin in the connecting rod and check the
seating for play.
If the piston pin seating has excessive play:
Change the connecting rod and piston pin.
Place the piston pin in the piston and check the seating for
play.
If the piston pin seating has excessive play:
Replace the piston and, if necessary, the cylinder and
piston pin.
f)
of the piston
:S 0.08 mm (:S 0.0031 in)
(IUI p. 313)
(IUI p. 197)