The twenty Xs650s 1981 (b) Usa Front Master Cylinder component parts are all listed in this schematic.
The most reasonably priced component used on the Xs650s 1981 (b) Usa Front Master Cylinder is the Screw, Flat Head (2m0).
Some items from this specific schematic: Bolt, Union (481), Joint, Hose, Brake 1, Diaphragm, Reservoir.