Parts such as the Water Pump: Bolt, Impeller, O Ring,water Pump Holder, Pump Assy,water are included in the Vzr1800n Boulevard M109r 2006 (k6) California (e33) Water Pump parts fiche.
On this parts fiche the Screw is the most specified component.
The Screw is the lowest priced item on this Water Pump schematic.