Shift Mechanism Removal
Take off the shift pedal. Carefully remove any burrs around the end of the shaft.
Remove the clutch.
Put the transmission in gear and lock the rear brake to remove the input shaft gear.
Compress the ratchet mechanism and pull the shift shaft out of the crankcase.
The large input shaft gear must go on with the recessed side toward the crankcase. The small gear can go on either way.
Tighten the input shaft gear nut to 5.4 – 7.5 kg-m (39 – 54 lb-ft) of torque. The end of this nut drives the oil pump. If it loosens in use, the engine may be damaged by lack of lubrication.