Yamaha YZ125N1 Service Manual page 148

ENGINE REMOVAL
2. Install:
9Lock washer 1
9Nut (drive sprocket) 2
NOTE:
Tighten the nut while applying the rear brake.
3. Bend the lock washer tab to lock the nut.
4. Install:
9Chain cover 1
9Screw (chain cover) 2
4-61
ENG
60 Nm (6.0 m•kg, 43 ft•lb)
5 Nm (0.5 m•kg, 3.6 ft•lb)