The component with the lowest price in the OIL FILTER/WATER PUMP schematic is the Bolt,flange,6x12.
Some items from this specific schematic: O-ring 32.95x2.62, O-ring,18.3x2.3, Pump Assy,water, Clamp,water Hose.
This schematic depicts all components used in the Gl1500 Goldwing 1988 (j) Switzerland / Kph Oil Filter/water Pump partslist.