The most reasonably priced component used on the Gl1500a Goldwing Aspencade 1998 (w) Usa California Swingarm is the Bolt,flange,8x32.
Check out any of the fifteen Swingarm components enlisted.
Some items from this specific schematic: Swingarm Assy,rea, Circlip, Spg.,prop Shaft, Oil Seal,27x43x7.