The most reasonably priced component used on the Gsx250s 1982 (z) General Export (e01) Crankcase (model Z) is the Bolt (6x90).
Parts such as the Crankcase (model Z): 01550-10903, Bolt(10x210), Bolt,under, Bolt 10x215 are included in the Gsx250s 1982 (z) General Export (e01) Crankcase (model Z) parts fiche.
In this schematic the "Bolt" is used most often.