Parts such as the F-23 Taillight: Taillight Unit, Rubber,taillight, Bolt,hex 6x28, Cover,coupler are included in the Xr500r 1981 (b) F-23 Taillight parts fiche.
This schematic depicts all components used in the Xr500r 1981 (b) F-23 Taillight partslist.
The F-23 Taillight assembly is constructed from several parts from which the Taillight Unit is the most expensive.