Yamaha YZ250(P)/LC Owner's Service Manual page 340

ENGINE REMOVAL
2. Install:
9
Lock washer 1
9
Nut (drive sprocket) 2
NOTE:
Tighten the nut while applying the rear brake.
3. Bend the lock washer tab to lock the nut.
4. Install:
9
Chain guide 1
9
Chain cover 2
9
Screw (chain cover) 3
4-64
ENG
75 Nm (7.5 m•kg, 54 ft•lb)
8 Nm (0.8 m•kg, 5.8 ft•lb)