Installing The Transmission - Yamaha YZ125X 2021 Owner's Service Manual

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).
EAM30157

INSTALLING THE TRANSMISSION

1. Install:
• 6th pinion gear (21T) "1"
• 3rd/4th pinion gear (17T/17T) "2"
• 5th pinion gear (20T) "3"
• 2nd pinion gear (15T) "4"
(to main axle "5")
TIP
Apply the molybdenum disulfide oil on the inner
and end surface of the idler gear and on the in-
ner surface of the sliding gear, then install.
2. Install:
• 2nd wheel gear (29T) "1"
• 5th wheel gear (24T) "2"
• 3rd wheel gear (27T) "3"
• 4th wheel gear (23T) "4"
• 6th wheel gear (23T) "5"
• 1st wheel gear (31T) "6"
(to drive axle "7")
TIP
• Apply the molybdenum disulfide oil on the in-
ner and end surface of the idler gear and on the
inner surface of the sliding gear, then install.
• Apply the molybdenum disulfide grease on the
inner surface of the 4th wheel gear, then install.
3. Install:
• Washer "1"
• Circlip "2"
New
TIP
• Be sure the circlip sharp-edged corner "a" is
positioned opposite side to the washer and
gear "b".
• Be sure the circlip end "c" is positioned at axle
spline groove "d".
4. Install:
• Collar "1"
TIP
• Apply the lithium soap base grease on the oil
seal lip.
5-45
TRANSMISSION