The Screw-washer,6x20 is the cheapest item from this partsfiche.
Parts such as the Air Cleaner: Cover, A/clnr Hsg, Band,air Cleaner, Elemt,air Cleaner, Plug,brthr Tube are included in the Cx650c Custom 1983 (d) Usa Air Cleaner parts fiche.
In this schematic the "Collar, Chain Guard" is used most often.