Husqvarna 50 Workshop Manual page 27

On models so equipped, assemble the rim sprocket to
the clutch drum. Lightly lubricate the clutch drum needle
bearing then slide the washer, needle bearing and clutch
drum onto the crankshaft.
Install the clutch hub and shoes. Tighten the clutch hub
to 30-40 Nm (22.1 -29.5 ft. Ibs.).
Never start the saw without the bar, chain and chain
brake installed. Due to the rapid acceleration and
deceleration of the engine, the clutch could come
loose and cause severe injuries.
WARNING !