First, I have searched the forum and done a ton of research on this subject before posting. I didn't find specifically what I am looking for so thanks in advance for the advice. My 2009 WR450F has the following setup Year: 2009Model (450):Cam Timing (WR/YZ): Don't knowMain jet: 165Pilot Jet: 48PAJ: 105Leak Jet: 55Starter Jet: 72Fuel screw (turns out): ?Needle Model/Clip position: 5th clip up from the bottomGrey Wire Mod (Y/N): YesTPS Connected (Y/N): YesAirbox Snorkel/Lid (on or off): OFFAIS Removed (Y/N): YesAirfilter Brand: Twin AirExhaust Brand: FMF 4.1 with powerbomb headerAverage Altitude: 800-1000'Average Temperature: 60-90FAverage Humidity: 70-80 The symptoms I am trying to correct is the steady RPM stutter and backfire-popping on decel (real bad) The bike starts good off button and idles fine. I had Yamaha dealer check exhaust with analyzer and they said it passes. I have tried disconnecting the TPS and although it does make it run smoother, it still stutters pretty bad. Since I DS the bike I really need it to run smooth on pavement. I even replaced the TPS earlier this year and had no effect. i have taken the bowl off and cleaned all the jets and every little hole I could find with carb cleaner. I checked the exhaust front to back, put in fresh gasket, and verified no leaks. Re-packed the muffler. Before I put the carb back on, I would greatly appreciate any advice as to what I can do to make it run better. Again, thanks in advance!!!