883 running rough with new CV Tuner Kit

I just installed my new tuner kit on my 2004 883. The bike had been backfiring through the carb and and would cough and run poorly when starting out after the engine was warm before I installed the new kit. I installed the new tuner kit along with a screamin eagle air cleaner and a set of vance & hynes slip on mufflers. I used the stage 1 jet numbers shown in the table. The bike runs real well now with the throttle open on the main jet but the bike is still the same when starting out from a stop with a warm engine. It seems like it might be getting too much gas when you first open the throttle.

When I was installing the kit I checked the vacuum diapraghm and it looked ok so I reused it. I did put a new accelerator pump diapraghm in when I had the carb apart. I had thought that maybe the engine wasn't getting enough gas so that's why I changed it.
I experimented with the EZ adjust mixture screw and it didn't really have any effect. I went from 1 1/2 to 4 1/2 turns. I put got a new sleeve and replaced it at the manifold so I know the connection with the carb is good. I also checked for vacuum leaks but didn't find any.
When I looked at the plugs they had a lot of carbon.
Would a bad needle valve on the float cause these kind of symptoms?
If not, what else could I try?

You can try a smaller pilot jet and if your best idle is 1 turn or less the pilot is too big...more than 3 turns it's too small....turn up your idle speed a bit,it makes it easier to notice a difference in idle...also check to make sure your enrichener cable is seated all the way,another thing to check on the enrichener cable is the end that goes in the carb...if the rubber ring in the end is convexed,(lower than the outside ring on the cable) it won't seat properly and give you a rich condition...good lucK keep us posted

Ken, I got a new enricher plug from the dealer and changed it. I also changed the needle on the float. when i had the carb apartagain I cleaned the idle passages with compressed air and carb cleaner like you suggested. At first I thought that solved it but after the bike runs for a half hour or so it will start having problems when you come to a stop. When you come to a stop and roll on the throttle nothing happens, the engine just stumbles, then if you feather the throttle there will be some backfiring through the carb and eventually the engine opens up. It will run good from there until you come to a stop again. At first I assumed it was running rich, but there isn't any black smoke or anything so I am not sure now. As I said in my earlier post the bike was doing this before I installed the tuning kit. I was thinking of checking for a vacuum leaks again after the bike ran for a while because it seems to run pretty well for the first half hour of riding. Maybe something is leaking after it heats up? Any ideas on what I should try next?

"At first I thought that solved it but after the bike runs for a half hour or so it will start having problems when you come to a stop. When you come to a stop and roll on the throttle nothing happens, the engine just stumbles, then if you feather the throttle there will be some backfiring through the carb and eventually the engine opens up. It will run good from there until you come to a stop again."

I have your answer for you! This problem acts like a carb problem, but it is not. You need to replace your Crank Position Sensor. On 2004, 2005, 2006 Sportster this crappy sensor starts failing. It will run fine until it warms up, then will not engage from idle. You need part number 32804-04B. Apparently, the B designation means that HD has re-designed the sensor twice. This problem will actually throw an error code you can access in the speedometer.

Thanks for the reply. You are right about he crankshaft postion sensor being the problem. I was told by someone else in te summer about it. Since it was replaced along with the new jets the bike is running great. I should have posted that here earlier so if somone else had a similar problem they would know what to try.

There ya go...good to hear...