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Backfire

01 Roadking

01 Roadking

Member
I bought my roadking this past May. When I would downshift going downhill it would backfire a little bit. In July I had the stock mufflers altered, ( I know I may catch a little flack for that ), now the backfiring is worse. I had a fuel management system installed and it still backfires the way it did before I had it put on. The bike seems to run perfectly. What all could be causing this? Could leaks elsewhere in the exhaust system do it? BTW it's a 2001 RK.
 
01 Roadking said:
I bought my roadking this past May. When I would downshift going downhill it would backfire a little bit. In July I had the stock mufflers altered, ( I know I may catch a little flack for that ), now the backfiring is worse. I had a fuel management system installed and it still backfires the way it did before I had it put on. The bike seems to run perfectly. What all could be causing this? Could leaks elsewhere in the exhaust system do it? BTW it's a 2001 RK.
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Is this backfire just on decel , what fueler did you attach to it , what is "altered the stock mufflers" actually ?????????
 
Yes, the backfire is only during decel. I have forgotten the brand name of the fuel manegement system, I will have to pull the seat and look but, I know it has three adjustmens on it and was installed by a reputable local repair shop. I had the stock mufflers bored out which will cause the engine to run lean, thus the need for the fuel management. I know other people who have done this and didn't have the same problem.
 
Backfire conditions are caused by lean conditions and or fresh air getting into the exhaust caused by a leak at a connection, for the exhaust leak test, start the engine and have a friend block off both outlets of the mufflers using a couple rags in each hand, if there is a leak you should be able to hear the air pushing past the leaking connection.
Lean conditions can be found with carb cleaner. With plastic straw in the nozzle, engine at idle, spray around the intake, if a vacuum leak is hit the idle will raise. Another cause for a lean condition is the fuel filter, a restricted filter can allow proper pressure, but low volume, leading to a lean condition. 01 by now should have had a couple fuel filters replaced. My 03 back fired very bad under decel, after doing the above, I found my fuel filter was plugged. 22,000 miles, after replacing it no mater how hard I tried I had no backfire.
 
O.K. thanx. I will change the filter for sure.I bought the bike in June and I don't know when it was changed last.
 
01 Roadking said:
Yes, the backfire is only during decel. I have forgotten the brand name of the fuel manegement system, I will have to pull the seat and look but, I know it has three adjustmens on it and was installed by a reputable local repair shop. I had the stock mufflers bored out which will cause the engine to run lean, thus the need for the fuel management. I know other people who have done this and didn't have the same problem.
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the fueler was added and set after the muffs were bored out ,which will cause a loss of back pressure. Have you checked the header pipes for leaks ? sorry for not knowing this - but is it carbed or FI ?
 
It's fuel injected. I was thinking it would be a good idea to check the entire exhaust system to be sure nothing was loose causing a leak.
 
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