The most reasonably priced component used on the St1100a Paneuropean 1998 (w) Italy Oil Pump is the Washer,plug,drain 12.
This Pump Assy.,oil is the most expensive of the items that make up this Oil Pump assembly.
Some items from this specific schematic: Pipe Comp,oil, Washer,plug,drain 12, Bolt,flange,6x14, Bolt,flange,6x80.