Parts such as the Transmission: Brg,r-b 6301 37mm 60g Nt, Gear, 2nd Pinion, Circlip (4v0), Gear, 4th Pinion are included in the Yfm80n 1985 Moto-4 Transmission parts fiche.
The Transmission is made up of components including this Drive Axle Assy which is the most expensive.
The lowest price component in this Transmission parts-list fiche is the Washer, Plate (29f).