fifteen components are shown in this Gsxr750 1991 (m) (e01 E02 E04 E15 16 17 18 21 22 24 25 34 39 53) Oil Pump exploded diagram.
Some items from this specific schematic: Bolt, Bolt, Pump Assembly,oil, Pipe,oil Outlet.
The lowest price component in this Oil Pump parts-list fiche is the Pin.