The twenty-three Kz750e1 1980 Usa Canada Rear Master Cylinder ('80 Kzy 50 component parts are all listed in this schematic.
The Pin-cotter,2.0x15 is the cheapest item from this partsfiche.
Some items from this specific schematic: Hose,brake,outside, Bolt,8x28, Hose-brake,l=395, Rod-assy-brake.