The component with the lowest price in the TRANSMISSION COVER schematic is the Bolt,flange,6x14.
On this parts fiche the Bolt,flange,6x25 is the most specified component.
Parts such as the Transmission Cover: Boss, Oil Filter, Bolt,flange,6x14, Dowl Pin,14x12, Pipe,oil Path are included in the Gl1500 Goldwing 1988 (j) England / Mkh Transmission Cover parts fiche.