Yamaha XT250X 2008, Руководство по обслуживанию, Страница: 174 / 282

CYLINDER AND PISTON
5-28
EAS24440
CHECKING THE PISTON PIN
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.
EAS24450
INSTALLING THE PISTON AND CYLINDER
1. Install:
●
Top ring “1”
●
2nd ring “2”
●
Lower oil ring rail “3”
●
Upper oil ring rail “4”
●
Oil ring expander “5”
NOTE:
Be sure to install the top ring and 2nd ring so that
the manufacturer’s marks or numbers face up.
2. Install:
●
Piston “1”
●
Piston pin “2”
●
Piston pin clips “3”
NOTE:
●
Apply engine oil to the piston pin.
Piston ring end gap
Top ring
End gap (installed)
0.19
–
0.31 mm (0.0075
–
0.0122 in)
Limit
0.60 mm (0.0236 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)
Piston pin outside diameter
15.991
–
16.000 mm
(0.6296
–
0.6299 in)
Limit
15.971 mm (0.6288 in)
Piston pin bore inside diameter
16.002
–
16.013 mm
(0.6300
–
0.6304 in)
Limit
16.043 mm (0.6316 in)
Piston-pin-to-piston-pin-bore clearance
=
Piston pin bore diameter “b” -
Piston pin outside diameter “a”
Piston-pin-to-piston-pin-bore
clearance
0.002
–
0.022 mm (0.0001
–
0.0009
in)
New
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