30/ENGINE - WORK ON INDIVIDUAL PARTS
114
19.25
Checking/measuring the piston
600253-01
–
Check the piston bearing surface for damage.
» If the piston sliding surface is damaged:
–
Change the piston and, if necessary, the cylinder.
–
Check that the piston rings can move easily in the piston ring grooves.
» If the piston ring is stiff:
–
Clean the piston ring groove.
Tip
Use an old piston ring to clean the piston ring groove.
–
Check the piston rings for damage.
» If the piston ring is damaged:
–
Change the piston ring.
Info
Mount the piston ring with the marking facing upward.
–
Check the piston pin for discoloration or signs of wear.
» If the piston pin has strong discoloration or signs of wear:
–
Change the piston pin.
–
Insert the piston pin into the connecting rod and check the bearing for play.
» If the piston pin bearing has too much play:
–
Change the connecting rod and the piston pin.
200161-10
–
Measure the piston at the piston skirt, at right-angles to the piston pin.
Specification
Piston diameter (450 XC ATV)
Size I
88.916… 88.946
mm (3.50062…
3.5018
in)
Size II
88.926… 88.958
mm (3.50102…
3.50228
in)
Piston diameter (525 XC ATV)
Size I
94.932… 94.960
mm (3.73747…
3.73858
in)
Size II
94.940… 94.968
mm (3.73779…
3.73889
in)
Info
Piston size
is marked on the piston head.
19.26
Checking the piston ring end gap
200163-10
–
Remove the piston ring from the piston.
–
Place the piston ring in the cylinder and align it with the piston.
Specification
under the upper edge of the cylinder
10
mm (0.39
in)
–
Measure the end gap with feeler gauge
.
Specification
Piston ring - end gap
Compression ring
<
0.80
mm (<
0.0315
in)
Oil scraper ring
<
1.00
mm (<
0.0394
in)
» If the end gap is greater than the specified value:
–
Check/measure the cylinder. (
» If the cylinder wear is within the tolerance range:
–
Change the piston ring.
–
Mount the piston ring with the marking facing toward the piston head.