I have a 09 road king. My setup was screaming eagle AC, bub7 true duals head pipes and kerker muffler with standar kerker core. also a custom dyno screaming eagle race tuner map that worked fine with kerkers.

I bought the supertrapp se mufflers in order to try them with my duals. I removed the kerker muflers and I realized that there was some gasoline where the headpipe fits the muffler, it was unburned gasoline and that happended with the true duals, kerker mufflers and the dyno map for duals. any ideas about why this thing happened?

I cleaned them and install supertrapps with my bub 7 true dual headers and the same map. after that, I started the bike, it took a bit longer to start and when it did it left muffler split a flame with a backfire. I thought, bad thing! checked everything 3 times and everything was ok, so I strarted the bike again, this time seem to start easyer. I left the bike iddle and warm up and then I hit throttle 2 or 3 times in order to hear supertrapps se sound compared to kerkers, surprise, this time was the right mufler the one that split a flame and a small explosion...

never happend anything like this with kerker mufflers... I dont know if the problem is the muffler (supertrapp baffle is more restrictive than kerker), the map, the drop of gasoline in the headder or if it just happend because they are new and there could be some mat that set on fire... Got any ideas about what could be?

after that I went out for a ride in order to see if bike does the same thing again, a friend of mine was drivin behind me in order to see if something was going wrong. and here comes the biggest surprise...

first I was riding slow, changing gears at low rpm, bike runs great so I think I can drive a little more aggresive, I hit the gas and bike pulls like a crazy horse, low end torque is really good, similar to stock 2-1-2 headpipe and much better than true duals with kerker open baffle mufflers.

midrange is AWSOME btw 2500 and 4000 the bike is a rocket is a beast it is incredible the change those mufflers make ( I remember ther was a deep in the torque curve arround 2700 rpm, now no only theres no deep, my dyno *** thinks that the torque curve peak is arround this rpm range, just hit gas at low rpm and when it comes to up to 3000 bikes acts like an automatic car when you hit the booster kick and the car reduces one or two gears in orther to increase spped at max. this is incredible)

4th gear pushes up to 80mph, I rised 98mph in 5th with no problems and I didnt want to go faster but im sure I could, I thought supertrapps where going to be a plug at high rpm but they work like kerkers or even better...

So beside the backfire issue (bike didnt do that again during the ride) I can recomend supertrapp se series with true duals headers as the best combo I had on and HD (sound is a little too quiet but I supousse that after a few miles the map will burn a bit and they will get louder)

So bike now rides great but I am worry for the backfire problem, it only happend the first 2 time I started the bike but it is not a good thing and Im afraid of ride the bike if that backfire can be a problem for the engine or damage something.

please excuse my english, im from Spain. I hope you understand my post and give me some ideas about why this backfire happend. btw I didnt use any oil or anything like that when I installed mufflers and I cleaned everything well before I satarted the bike.

Thank you

 

I would rule out the new mufflers as a problem if the old ones had raw fuel in em when you took them off.

 

I'm new to bikes and have a 2000 RK fuel injected with Reinhart TD's. First I don't think you should have raw fuel in the muflers! Are you sure it wasn't condensation that smells like gas? I think your fuel managment should be redone with any muffler change. Did it backfire with the old mufflers as bad? I don't think you said. Even if the map is wrong or off for the Super traps it should still start.
These are just thought I had. How has it been running lately?

 

He stated he already has a Stage 1 map. It should be fine.

 

no it didnt backfire with the old mufflers at all. I think it could be condensation.. it was a brown liquid (like oil) that smels like gas. It was not oil cause it was not that thick.

bike didnt do that again, I think maybe it autotune the mix at start and iddle after a ride usin the o2 in close loop... anyway I have reflased the bike with the same map to see if it helps

I wrote supertrapp and they told me that maybe a fuel inyector is stuck open because of gas sediments, I dont think so as I always put premium gas... I can try to put one of those products that cleans inyectors but I dont know if they are ok with hd engines... guys at supertrapp customer service dont think it is because of using the same sert map because there's no such a biig diference btw kerker and supertrapp cores...


do you think the f..... trash stock compensator is involved in this issue? maybe spark time is too foward?