The most expensive part in this assembly is the Pump,assy.,oil.
With a quantity of two pieces, the Pin,dowel,8x10 is the most used part in the OIL PUMP diagram.
Parts such as the Oil Pump: Bolt,flange,6x45, Rotor,oil Pump, Pin,dowel,8x10, Bolt,flange,6x35 are included in the Trx300fw Fourtrax 1989 (k) Canada Oil Pump parts fiche.