The sixteen Zr50sk 1984 (e) (e02 E16 E21) Handle Switch component parts are all listed in this schematic.
On this parts fiche the Screw 5x20 is the most specified component.
A sample from the products for the Handle Switch include: Lever,brake, Screw 5x20, Grip, Lh, Lever Assy, Clutch.