Parts such as the Transmission: Washer, Conical Spring (3l4), Brg,r-b 6203rs 40mm 63.3g Ky, Brg,r-b 6300 35mm 58g Nt, Drive Axle Assy are included in the Ca50s 1986 Riva Transmission parts fiche.
The Transmission assembly is constructed from several parts from which the Main Axle Comp. is the most expensive.