I have an '06 trx 450 ER. I took it out the other day and it ran fine for a couple of minutes, then it started to sputter and backfire out of the exhaust (shooting flames out of my HMF pipe) it feels like i lose a bunch of hp. So i replaced the spark plug, COMPLETELY took the carb apart and cleaned the sh*t out of it. I cleaned the air filter and its still doing the same thing. It starts up just fine and i can roll into the throttle and its not nearly as bad as when i hammer down on it. Can anyone help save my weekend of riding?!?!