The most reasonably priced component used on the Vzr1800n Boulevard M109r 2006 (k6) California (e33) Oil Pan - Oil Pump is the Gasket(5.8x13x1.2) (nas).
On this parts fiche the Bolt is the most specified component.
Parts such as the Oil Pan - Oil Pump: Circlip,10mm, Gear,oil Pump Drive, Pin(4x15.8), Rotor Set,oil Pump are included in the Vzr1800n Boulevard M109r 2006 (k6) California (e33) Oil Pan - Oil Pump parts fiche.