The Tapping,5x12 is the lowest priced item on this Rear Swingarm/chain Case schematic.
On this parts fiche the Bush,rear Fork is the most specified component.
Parts such as the Rear Swingarm/chain Case: Bolt,flange,6x10, Nut,u,14mm, Joint Zj,drive Ch, Spg-washer 10mm are included in the Cb250 2001 (1) Portugal Rear Swingarm/chain Case parts fiche.