Yamaha YZ 2018 Series Owner's Service Manual page 273

EASB29B291
CHECKING THE SHIFT DRUM ASSEMBLY
1. Check:
• Shift drum groove
Damage/scratches/wear  Replace the
shift drum assembly.
• Shift drum segment "1"
Damage/wear  Replace the shift drum as-
sembly.
EASB29B292
CHECKING THE TRANSMISSION
1. Measure:
• Main axle runout
(with a centering device and dial gauge "1")
Out of specification  Replace the main ax-
le.
Main axle runout limit
0.08 mm (0.0032 in)
2. Measure:
• Drive axle runout
(with a centering device and dial gauge "1")
Out of specification  Replace the drive ax-
le.
Drive axle runout limit
0.08 mm (0.0032 in)
3. Check:
• Transmission gears
Blue discoloration/pitting/wear  Replace
the defective gear (s).
• Transmission gear dogs
Cracks/damage/rounded edges  Replace
the defective gear (s).
4. Check:
• Transmission gear movement
Rough movement  Replace the defective
gear (s).
EASB29B293
INSTALLING THE TRANSMISSION
1. Install:
• 6th pinion gear (27T) "1"
• 3rd/4th pinion gear (18T/21T) "2"
• Collar "3"
• 5th pinion gear (23T) "4"
• 2nd pinion gear (16T) "5"
(to the main axle "6")
TIP
Before installation, apply molybdenum disulfide
oil to the inner and end surface of the idler gear
and to the inner surface of the sliding gear, then
install.
1
6
5-76
TRANSMISSION
5
4
3
2
M