Parts such as the Exhaust Pipe - Muffler (ca160): Rubber Stand, Diffuser, Spg-washer 10mm, Washer,spring,6mm are included in the Ca160 Touring 1966 Usa Exhaust Pipe - Muffler (ca160) parts fiche.
With four applications this Nut,hex 6mm is the most specified part.
Check out any of the eighteen Exhaust Pipe - Muffler (ca160) components enlisted.