A sample from the products for the Front Wheel - Disk include: Valve,rim(dunlop), Dust Seal,40x50x5, Retainer,gear Box, Collar,distance.
On this parts fiche the Bolt,ubs,8x33 is the most specified component.
The most reasonably priced component used on the Cx500c Custom 1981 (b) Germany / Full Power Front Wheel - Disk is the Mark,spoke Plate.