Hoping for some ideas on where to look. A few miles after leaving the house the other day my bike stumbled and sputtered a bit. Bike was cold and just starting to warm up. I didn't think much of it until the next day when stopped at a stop sign again a few miles after leaving my house on a cold bike. This time the idle went up to 1200 RPM and when I went to rev it the bike again gave me a sputter for a few seconds. Each time it recovered within a few seconds. I ride this bike alot and have fresh gas in it. I changed the plugs and cleaned the air filter. Didn't help. It is doing this everytime I ride now. I am hoping someone might have an idea of what it could be. The only mods to my bike are Ness Big Sucker, Stage 1 flash and duals. I have not done any work lately so it's not due to any changes I have made. The bike runs great after this little warm up sputter. The only thing that i can think it might be is a sensor of some sort.