Parts such as the F-12 Fuel Tank: Mark,r.fuel Tank, Band,wire, Pkg,fuel Tank Cap, Cushion,fr.tank are included in the Xr250r 1982 (c) F-12 Fuel Tank parts fiche.
The most reasonably priced component used on the Xr250r 1982 (c) F-12 Fuel Tank is the Bolt,hex., 6x16.
On this parts fiche the Collar Tank Sett is the most specified component.