The Washer,screw 4x12 is the lowest priced item on this Fr. Brake Master Cyl. schematic.
On this parts fiche the Washer,oil Bolt is the most specified component.
Parts such as the Fr. Brake Master Cyl.: Cylinder Assy Fr, Joint,two Way, Bolt,flange,6x25, Diaphragh are included in the Cb750sc Nighthawk 750 1982 (c) Usa Fr. Brake Master Cyl. parts fiche.