Yamaha YZF-R25, Руководство по обслуживанию

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CYLINDER AND PISTONS
5-37
EAS30293
CHECKING THE PISTON PINS
The following procedure applies to both of the
piston pins.
1. Check:
• Piston pin
Blue discoloration/grooves
→
Replace the
piston pin and then check the lubrication sys-
tem.
2. Measure:
• Piston pin outside diameter “a”
Out of specification
→
Replace the piston pin.
3. Measure:
• Piston pin bore diameter “b”
Out of specification
→
Replace the piston.
4. Calculate:
• Piston-pin-to-piston-pin-bore clearance
Out of specification
→
Replace the piston pin
and piston as a set.
EAS30294
INSTALLING THE PISTONS AND CYLINDER
The following procedure applies to both of the
pistons.
1. Install:
• Oil ring expander “1”
• Lower oil ring rail “2”
• Upper oil ring rail “3”
• 2nd ring “4”
• Top ring “5”
Piston ring
Top ring
End gap (installed)
0.10–0.25 mm (0.0039–0.0098
in)
Limit
0.40 mm (0.0157 in)
2nd ring
End gap (installed)
0.30–0.45 mm (0.0118–0.0177
in)
Limit
0.60 mm (0.0236 in)
Oil ring
End gap (installed)
0.10–0.35 mm (0.0039–0.0138
in)
a. 40.0 mm (1.57 in)
Piston pin outside diameter
14.995–15.000 mm (0.5904–
0.5906 in)
Limit
14.975 mm (0.5896 in)
Piston pin bore inside diameter
15.002–15.013 mm (0.5906–
0.5911 in)
Limit
15.043 mm (0.5922 in)
• Piston-pin-to-piston-pin-bore clearance =
Piston pin bore inside diameter “b” -
Piston pin outside diameter “a”
Piston-pin-to-piston-pin-bore
clearance
0.009–0.025 mm (0.0004–0.0010
in)