When I bought the bike above from a private party, it was equipped with an aftermarket muffler, Akrapovic; he also gave me the stock muffler. I didn't care for the noise, so I put the stocker back on. Anyone interested in buying the Akrapovic? IF so, let me know at Thumpower@aol.com. IT retails for $900 - I'll sell it to you for $500. Otherwise, it goes on Ebay. The bike only had 4k miles on it when I bought it.