Parts such as the Exhaust 250b/c - 400b/c: Screw, Bind, Silencer, Washer Plate 214147660000, Ybs67-8 Washer, Spring are included in the Dt400 1975 Usa Exhaust 250b/c - 400b/c parts fiche.
Of all the components used in this assembly the Exhaust Pipe Assy is the most expensive.