The most reasonably priced component used on the Gl1500a Goldwing Aspencade 1998 (w) Australia / Kph Transmission Cover is the Bolt,flange,6x14.
On this parts fiche the Bolt,flange,6x25 is the most specified component.
Some items from this specific schematic: Bolt,flange,6x14, Gasket,transmissi (nas), Dowl Pin,14x12, Bolt,sealing,20mm.