The most reasonably priced component used on the Cb550k 1978 Usa Stand / Step is the Washer,plain, 6mm.
Parts such as the Stand / Step: Rubber,pillion, Washer,plain,6mm, Bolt,flange,10x28, Inner Pipe,step are included in the Cb550k 1978 Usa Stand / Step parts fiche.
On this parts fiche the Collar No Bracket is the most specified component.