The most reasonably priced component used on the Cb250 Nighthawk 1991 (m) Usa Oil Pump is the Screw,cross 5x10.
Some items from this specific schematic: Gasket,oil Pomp (nas), Oil Pump Assy, Screw,cross 5x10, Screen,oil Filter.
This Oil Pump Assy is the most expensive of the items that make up this Oil Pump assembly.