Yamaha BEARTRACKER YFM250XC, Руководство по обслуживанию

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4 - 33
ENG
INSPECTION AND REPAIR
2nd steps
●
Measure the piston skirt diameter “P”
with a micrometer.
b
4 mm (0.16 in) from the piston bottom edge
●
If out of the specification, replace the pis-
ton and piston rings as a set.
3rd steps
●
Find the piston-to-cylinder clearance with
following formula.
●
If out of the specification, rebore or
replace the cylinder, and replace the pis-
ton and piston rings as a set.
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PISTON RING AND PISTON PIN
Piston ring
1.Measure:
●
Side clearance
Use the Feeler Gauge
1 .
Out of specification
→
Replace piston and/
or rings as a set.
NOTE:
Eliminate carbon deposits from the piston
ring grooves and rings before measuring
the side clearance.
Piston skirt Diameter “P”
Standard
70.92 ~ 70.97 mm
(2.792 ~ 2.794 in)
Oversize 2 71.50 mm (2.815 in)
Oversize 4 72.00 mm (2.846 in)
Piston-to-cylinder clearance =
Cylinder bore “C” –
Piston skirt diameter “P”
Piston-to-cylinder clearance:
0.04 ~ 0.06 mm
(0.0016 ~ 0.0024 in)
< Limit >:
0.15 mm (0.0059 in)
4