Parts such as the Cam Shaft - Valve: Washer, Seat,valve Spring, Sprocket,camshaft(nt:42), Valve,intake are included in the Dr500s 1988 (j) Cam Shaft - Valve parts fiche.
With eight applications this Cotter Valve is the most specified part.
The Pin is the lowest priced item on this Cam Shaft - Valve schematic.