I need help with my 05' V Star 1100 custom. I added Cobra pipes and now I'm getting a popping/backfire noise when decelerating and it sounds terrible. The bike runs great. I would appreciate any help I can get with this issue.

Can anyone help me here? How is this done, and will it hurt the performance of the bike at all? It has 3 rivets in the end of each pipe, how do I remove them and then what do I do after that? I am not much of a bike mechanic so any help I can get would be appreciated. Also, sometimes I...