The most reasonably priced component used on the Vl800t Boulevard C50 2011 (l1) Usa Californi Canad (e03 E33 E28) Throttle Body (vl800 E28) is the Screw.
On this parts fiche the Screw,throttle Cover is the most specified component.
The Throttle Body (vl800 E28) is made up of components including this Body Assy,thro which is the most expensive.