Yamaha RS90K Manuel D'atelier page 536

CRANKCASE
8. Measure:
• Piston pin bore inside diameter
Out of specification → Replace the piston.
Piston pin bore inside diameter:
19.004 ~ 19.015 mm
(0.7482 ~ 0.7486 in)
9. Calculate:
• Piston pin to piston pin bore clearance
Out of specification → Replace the piston pin
and piston as a set.
Piston pin to piston pin bore clearance =
Piston pin bore size –
Piston pin outside diameter
Piston pin to piston pin bore clear-
ance:
0.004 ~ 0.024 mm
(0.0002 ~ 0.0009 in)
<Limit>: 0.074 mm (0.0029 in)
10. Measure:
• Crankshaft runout
Use the V-blocks and a dial gauge.
Out of specification → Replace the crank-
shaft.
Dial gauge:
90890-03097, YU-03097
Crankshaft runout:
0.03 mm (0.0012 in)
5-59
ENG