Yamaha YZ250F(W), Руководство по эксплуатации для владельца

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ENG
CYLINDER AND PISTON
Piston ring
1. Measure:
• Ring side clearance
Use a feeler gauge
1
.
Out of specification
→
Replace the piston
and rings as a set.
NOTE:
Clean carbon from the piston ring grooves and
rings before measuring the side clearance.
2. Position:
• Piston ring
(in cylinder)
NOTE:
Insert a ring into the cylinder and push it
approximately 10 mm (0.39 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.
a
10 mm (0.39 in)
Side clearance:
Standard <Limit>
Top ring
0.030 ~ 0.065 mm
(0.0012 ~ 0.0026 in)
0.12 mm
(0.005 in)
2nd ring
0.020 ~ 0.055 mm
(0.0008 ~ 0.0022 in)
0.12 mm
(0.005 in)
3. Measure:
• Ring end gap
Out of specification
→
Replace.
NOTE:
You cannot measure the end gap on the
expander spacer of the oil control ring. If the oil
control ring rails show excessive gap, replace
all three rings.
End gap:
Standard <Limit>
Top ring
0.15 ~ 0.25 mm
(0.006 ~ 0.010 in)
0.50 mm
(0.020 in)
2nd ring
0.30 ~ 0.45 mm
(0.012 ~ 0.018 in)
0.80 mm
(0.031 in)
Oil ring
0.10 ~ 0.40 mm
(0.004 ~ 0.016 in)
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