Of all the components used in this assembly the Pump Assy,oil is the most expensive.
The O-ring 7x1.7 is the most widely applied product in the XR500 1980 (A) CANADA E-8 OIL-PUMP ( two times ).
The component with the lowest price in the E-8 OIL-PUMP schematic is the Screw,cross,5x12.