Yamaha YZ250 2022, Owner'S Service Manual

Page: 204 / 274

TRANSMISSION
5-42
EAM30153
REMOVING THE TRANSMISSION
1. Remove:
•
Main axle “1”
• Drive axle “2”
•
Shift cam
• Shift fork 3
•
Shift fork 2
• Shift fork 1
TIP
• Remove assembly carefully. Note the position
of each part. Pay particular attention to the lo-
cation and direction of shift forks.
•
Remove the main axle, drive axle, shift cam
and shift fork all together by tapping lightly on
the transmission drive axle with a soft hammer.
EAM30154
CHECKING THE SHIFT FORKS
1. Check:
•
Shift fork “1”
Wear/damage/scratches

Replace.
2. Check:
•
Shift fork movement
Unsmooth operation

Replace shift fork.
TIP
For a malfunctioning shift fork, replace not only
the shift fork itself but the two gears each adja-
cent to the shift fork.
EAM30155
CHECKING THE SHIFT DRUM ASSEMBLY
1. Check:
• Shift drum groove
Damage/scratches/wear

Replace the shift
drum assembly.
•
Shift drum segment
Damage/wear

Replace the shift drum as-
sembly.
EAM30156
CHECKING THE TRANSMISSION
1. Measure:
•
Main axle runout
(with a centering device and dial gauge “1”)
Out of specification

Replace the main axle.
2. Measure:
•
Drive axle runout
(with a centering device and dial gauge “1”)
Out of specification

Replace the drive axle.
Main axle runout limit
0.01 mm (0.0004 in)
Drive axle runout limit
0.01 mm (0.0004 in)