Check out any of the twenty-eight Fuel Tank components enlisted.
On this parts fiche the Bolt, Small Flange is the most specified component.
Parts such as the Fuel Tank: Valve Packing (nas), Hose (l30), Screw, Binding, Screw, Pan Head(3sx) are included in the Wr250f 2006 5umc Europe 1e5um-100e1 Fuel Tank parts fiche.