On this parts fiche the Bolt is the most specified component.
Parts such as the Fuel Cock: Lock Washer, Gasket,fuel Level Gauge (nas), Spring, Gasket(6.4x11.5x0.8) (nas) are included in the Gsx1100f 1988 (j) (e01 E18 E75 E76 E78) Fuel Cock parts fiche.
The Fuel Cock assembly is constructed from several parts from which the Gauge Assy,fuel Level Sender is the most expensive.