Parts such as the Oil Pump: Body,scavenge Oil, Cover,oil Pump, Bolt,flange,6x18, Bolt,flange,6x14 are included in the Gl1500 Goldwing 1989 (k) Usa California Oil Pump parts fiche.
On this parts fiche the Bolt,flange 6x32 is the most specified component.
The Oil Pump assembly is constructed from several parts from which the Pump Assy,oil is the most expensive.