The Pin(4x15.8) is the lowest priced item on this Oil Pump schematic.
Check out any of the twenty-one Oil Pump components enlisted.
Parts such as the Oil Pump: Strainer,engine Oil, Plug, Circlip, O Ring(d:2.4,id:73) are included in the Dr500 1983 (d) Usa (e03) Oil Pump parts fiche.