The Akrapovic muffers have a 60mm I.D. inlet.
If you find a set of muffler with that dimension, you should be good.
Just be sure you get the muffler clamps as the Akra units probably won't work.
Also, remember that Akrapovic oval mufflers were used on many different bikes (albeit with different lengths).
Expand your search to include bikes other than the RC51.
Then you can use the end cap to rebuild the damaged muffler.
The repair kit with packing, rivets, and carbon-fiber sleeve runs around $250 per muffler.
Last edited by SubSailor; 10-06-2012 at 09:58 PM.