Yamaha YZ426F(M)/LC, Owner'S Service Manual

Page: 396 / 608

4 - 81
ENG
CRANKCASE AND CRANKSHAFT
EC4N4101
Crankcase
1. Inspect:
●
Contacting surface
a
Scratches
→
Replace.
●
Engine mounting boss
b
, crankcase
Cracks/damage
→
Replace.
2. Inspect:
●
Bearing
Rotate inner race with a finger.
Rough spot/seizure
→
Replace.
3. Inspect:
●
Oil seal
Wear/damage
→
Replace.
EC4N4201
Crankshaft
1. Measure:
●
Runout limit
a
●
Small end free play limit
b
●
Connecting rod big end side clearance
c
●
Crank width
d
Out of specification
→
Replace.
Use the dial gauge and a thickness
gauge.
Dial gauge and stand:
YU-03097/90890-01252
Standard <Limit>
Runout
limit:
0.03 mm
(0.0012 in)
0.05 mm
(0.002 in)
Small end
free play:
0.4 ~ 1.0 mm
(0.016 ~ 0.039 in)
2.0 mm
(0.08 in)
Side
clearance:
0.15 ~ 0.45 mm
(0.0059 ~ 0.0177 in)
—
Crack
width:
61.95 ~ 62.00 mm
(2.439 ~ 2.441 in)
—