The lowest price component in this Exhaust parts-list fiche is the Washer(6a1).
With a quantity of four pieces, the Stud is the most used part in the EXHAUST diagram.
Parts such as the Exhaust: Joint, Exhaust, Washer, Special 1682161500, Gasket, Exhaust Pipe (mca), Pipe, Exhaust (r.h) are included in the Rd400 1978 Usa Exhaust parts fiche.