I have a 2007 ultra classic and I seen a stamped disk with a hole in it with a flange around it that you put in the left side exhaust right in front of the muffler ... it was around 5.00 dollars plus shipping ..it stops the air coming back up the pipe and causing a backfire. I can`t find it again... I went to there web site and seen it and now I can`t find it again...would someone help me. I have searched my history and still no luck.. PLEASE HELP ME FIND IT...in the article I was looking at had the true dual conversion pipe in it also..