Parts such as the Transmission: Cir Clip,28mm, O-ring,9.8x2.4, Washer,10.2mm, M-4 Gear,(25t) are included in the Cb750c 750 Custom 1981 (b) Usa Transmission parts fiche.
Check out any of the forty-four Transmission components enlisted.
The Transmission assembly is constructed from several parts from which the Shaft,counter is the most expensive.