Sportster EFI to Carburetor
I don't know but I have read about several people having trouble with their EFI equipped Sportsters. The bikes having problems that has riders at the local shop instead of out riding the bike and enjoying the road. Instead the engines begins to run like crap and the dealerships just can't seem to get it right after several attempts making owners wish they had never bought the darned thing in the first place, worse, making them want to trade it in for a Jap bike. It doesn't have to be this way. My understanding is that the newer Sporties (2004 & up) have an ignition system akin to the twincam engines and guess what; there is a company that has the cure for this ailment to give you a more trouble free steed with the ability to run a carburetor instead of the troublesome fuel injected engine.
Here is a link for your reading and informational pleasure complete with instructions on how to perform this upgrade conversion. The company is Altmann Motorcycle Ignitions in West Germany: