My '04 R1150RT has a 2 Brothers header pipe (part #005-9204) and a 2 Brothers round cannister muffler (C4 is the only marking on it). The charcoal cannister has also been removed. I would like to find a new slip-on cannister that fits the current header pipe (OD 50mm). I've repacked the 2 Brothers muffler twice but no change. The backfiring from this thing is atrocious!!! If you have any suggestions, please pass them along. Thanks.