Parts such as the Muffler: Pipe,exhaust,f, Pipe,exhaust,r, Bolt(8x16), Gasket,exhaust Pipe (nas) are included in the Vl800 Volusia 2001 (k1) Usa (e03) Muffler parts fiche.
In this schematic the "Bolt(8x25)" is used most often.
The Nut is the cheapest item from this partsfiche.