The sub assemblies and components that make up this Gear Change Drum/shift Fork(s) include this Sprocket-driven,rever, the most expensive part.
Check out any of the twelve Gear Change Drum/shift Fork(s) components enlisted.
Some items from this specific schematic: Washer,24.2x32x0.50, Circlip, Spacer,20.3x30x1.8, Shaft,idler.