Yamaha BEARTRACKER YFM250XC, Service Manual

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4 - 34
ENG
INSPECTION AND REPAIR
Side clearance
Standard Limit
Top
ring
0.03 ~ 0.07 mm
(0.001 ~ 0.003 in)
0.12 mm
(0.005 in)
2nd
ring
0.02 ~ 0.06 mm
(0.0008 ~ 0.0024 in)
0.12 mm
(0.005 in)
2.Position:
●
Piston ring
(into cylinder)
NOTE:
Insert the ring into the cylinder, and push it
approximately 20 mm (0.8 in) into the cylin-
der. Push the ring with the piston crown so
that the ring will be at a right angle to the
cylinder bore.
3.Measure:
●
End gap
Use a Feeler Gauge
1
Out of specification
→
Replace rings as set.
NOTE:
You cannot measure end gap on expander
spacer of oil control ring. If oil control ring
rails show excessive gap, replace all three
rings.
End gap
Standard Limit
Top
ring
0.15 ~ 0.30 mm
(0.006 ~ 0.012 in)
0.4 mm
(0.016 in)
2nd
ring
0.15 ~ 0.30 mm
(0.006 ~ 0.012 in)
0.4 mm
(0.016 in)
Oil ring
0.2 ~ 0.7 mm
(0.008 ~ 0.028 in)
–
Piston ring oversize
●
Top and 2nd piston ring
Oversize top and middle ring sizes are
stamped on top of ring.
Oversize 2 0.50 mm (0.0197 in)
Oversize 4 1.00 mm (0.0394 in)
4