Yamaha YZ125N1 Service Manual page 169

FRONT WHEEL AND REAR WHEEL
5-9
8. Install:
9Chain puller (right) 1
9Plain washer 2
9Nut (wheel axle) 3
NOTE:
Temporarily tighten the nut (wheel axle) at this
point.
9. Adjust:
9Drive chain slack a
Drive chain slack :
40~50 mm (1.6~2.0 in)
Refer to "DRIVE CHAIN SLACK ADJUSTMENT"
section in the CHAPTER 3.
10. Tighten:
9Nut (wheel axle) 1
9Locknut 2
CHAS
125 Nm (12.5 m•kg, 90 ft•lb)