The component with the lowest price in the E-6 OIL PUMP - OIL FILTER ROTOR schematic is the Screw,flat.4x12.
Some items from this specific schematic: Cover,pump Gear, O,ring.2,4x9,4, Gear,primary Driv, Body,oil Pump.
This schematic depicts all components used in the Xl125k4 U.s.a E-6 Oil Pump - Oil Filter Rotor partslist.