twenty-nine components are listed in the schematic for this Vt700c Shadow 1985 (f) Usa California Oil Pump .
A sample from the products for the Oil Pump include: Boss, Oil Filter, O-ring,14.7x3.7, O-ring,13.8x2.5, O-ring,13.8x2.5.
On this parts fiche the O-ring,14.7x3.7 is the most specified component.