Parts such as the Crank Balancer: Pin, Race,crk Bal Driven Gr Inner, Washer, Shim are included in the Dr250 1985 (f) Usa (e03) Crank Balancer parts fiche.
The most expensive part in this assembly is the Gear,crank Bal Driven(nt:46).
The Key 4mm is the lowest priced item on this Crank Balancer schematic.