On this parts fiche the Bolt-hex Head,10x25 is the most specified component.
The most reasonably priced component used on the Kt250-a2 Trial 1976 Usa / Mph Rear Hub/brake/chain is the Bolt-upset.
Parts such as the Rear Hub/brake/chain: Joint-chain,ek428sh, Bolt-upset, Axle,rear, Cam Shaft,rear Brake are included in the Kt250-a2 Trial 1976 Usa / Mph Rear Hub/brake/chain parts fiche.