On this parts fiche the Bolt, With Washer is the most specified component.
Parts such as the Jet Unit 2: Bolt, With Washer(65a), Circlip(6r7), Bolt, With Washer, Oil Seal(62t) are included in the Xl800y 2000 Jet Unit 2 parts fiche.
The Jet Unit 2 assembly is constructed from several parts from which the Shaft, Coupler is the most expensive.