Mainshaft/Sprocket/Hub

Fig. 95:

Inspect the splines on the hub and shaft and the teeth on the sprocket. Minor nicks and scratches can be smoothed with an oilstone, however, replace any part is damaged.
Check the contact surfaces in the sprocket bore and on the mainshaft. Minor nicks and scratches can be smoothed with 320 - 400 grit emery cloth but do not try to salvage the shaft if nicks or wear is severe.