The lowest price component in this Front Master Cylinder (kz650-c1) parts-list fiche is the Nut,6mm.
Parts such as the Front Master Cylinder (kz650-c1): Bolt,hex Head,6x45, Washer,lock,8mm, Damper Rubber-cal Hse, Stopper-boots are included in the Kz650c2 Custom 1978 Usa Canada / Mph Kph Front Master Cylinder (kz650-c1) parts fiche.
In this schematic the "Washer,10.5x15x1.5" is used most often.