In this schematic the "Bolt, Stud (6x40)" is used most often.
The most reasonably priced component used on the Xr250 1980 (a) Usa Front Fork is the Screw-washer,4x25.
Parts such as the Front Fork: Ring,oil Seal, Bolt,stud 2.6x28, Bolt,hex 6x8, Bolt,flange,6x10 are included in the Xr250 1980 (a) Usa Front Fork parts fiche.