Checking The Crankcase; Checking The Piston Pins - Yamaha EH63 Service Manual

PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT
1
2
3
4
5
6
7
8
9
10
a
Piston-to-cylinder clearance:
Limit:
f. If out of specification, replace the crankcase

CHECKING THE CRANKCASE

1.
Check:
• Crankcase
Damage  Replace.
• Bearing
Noise/wear/rotational failure  Replace.

CHECKING THE PISTON PINS

1.
Check:
• Piston pin
Blue discoloration/grooves  Replace the piston
pin, and then check the lubrication system.
2.
Measure:
• Piston pin hole inside diameter "a"
Out of specification  Replace.
Piston pin hole inside diameter:
Limit:
3.
Measure:
• Piston pin diameter "a"
Out of specification  Replace.
Piston pin diameter:
Limit:
a
3-56
0.012–0.051 mm (0.0004–0.0020 in) (EH63K/
EH64A/EH64K/EH65A/EH65B)
0–0.042 mm (0–0.0016 in) (EH72A/EH72B/
EH72K)
0.15 mm (0.0059 in)
assembly, and replace the piston and piston rings
as a set.
21.002–21.011 mm (0.8268–0.8272 in)
21.041 mm (0.8283 in)
20.989–21.002 mm (0.8263–0.8268 in)
20.969 mm (0.8255 in)