Piston Pin And Small End Bearing Inspection - Yamaha 40V Service Manual

POWR
CRANK SHAFT AND PISTON
Measuring
point "H"
10 mm
Standard
(0.4 in)
Over size piston diameter:
1*: 67.25 mm (2.648 in)
2: 67.50 mm (2.657 in)
*: Except for U.S.A.
2. Measure:
Piston pin boss inside diameter
Use a micrometer.
Out of specification → Replace.
Piston pin boss inside diameter:
18.008 ~ 18.015 mm
(0.7090 ~ 0.7093 in)

Piston pin and small end bearing inspection

1. Inspect:
Piston pin
Small end bearing
Signs of heat discoloration →
Replace.
Scratch/Damage → Replace.
2. Measure:
Piston pin diameter
Use a micrometer.
Out of specification → Replace.
Piston pin diameter:
17.995 ~ 18.000 mm
(0.7085 ~ 0.7087 in)
3. Check:
Free play (when the piston pin is
inserted in the piston.)
There should be no noticeable for the
play.
Free play exists → Replace the pin
and/or piston.
5-34
E
Piston diameter
66.940 ~ 67.000 mm
(2.6354 ~ 2.6378 in)