Yamaha YFM90RA Model Vehicle User Manual


 
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ENG
CYLINDER AND PISTON
EBS00251
CHECKING THE PISTON PIN
1. Check:
piston pin
Blue discoloration/grooves
Replace the
piston pin and then check the lubrication
system.
2. Measure:
piston pin outside diameter
Out of specification
Replace the piston
pin.
Piston pin outside diameter
12.996 ~ 13.000 mm
(0.5117 ~ 0.5118 in)
<Limit>: 12.960 mm (0.5102 in)
3. Measure:
piston pin bore diameter
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.
Piston pin bore diameter
13.002 ~ 13.008 mm
(0.5119 ~ 0.5121 in)
<Limit>: 13.040 mm (0.5134 in)
Piston-pin-to-piston-pin-bore clearance =
Piston pin bore diameter
Piston pin outside diameter
Piston-pin-to-piston clearance
0.002 ~ 0.012 mm
(0.0001 ~ 0.00047 in)
b
a
b
a