Now we have rules on posting??? Geez I having prob with my '06 450. I have a WB complete exhaust system that the packing has worn out. So while V&H is taking over ans won't have packing until late June. I went ahead and put the stock exhaust back on the bike. This thing is back firing like crazy. I checked the exhaust seal and everything seems to be good. I only change out the pilot to a 48 when I put the WB exhaust on it...Am I missing something here??? I just checked the intake valves and they are a little tight ...I mean barely... Would that cause the backfiring like its doing now??? Or do I need to search somewhere else?