Carb backfires normally have to do with poor tuning of the carberator. All the Race tuner does is adjust the ignition timing and rev limit of your ignition module. If you just added Ac and or pipes then you need to adjust the carb itself. Race tuner aint gonna help. What will help is a wideband 02 sensor with preferably an LCD display so you can see just how well your carb really is tuned.

 

Stick around long enough
You get info from those who have been there - done that - COOL[8D]

 

I own one of these: http://www.daytona-sensors.com/WEGO2.html Its the best $400 you will ever spend for your bike. I don't like to go to a dyno tuner, they cost alot of money by charging per run or per hour, and many times they still arent the most accurate since the bike tuning is done on a "simulated" load with an 02 sensor shoved into the back of the exhaust pipe which is far from optimal(It should be right next to the exhaust port on the cylinder head). And of course your still limited to how good the operator of the dyno is and how much he really cares about dialing in your bike perfectly.

The Wego, or devices similiar to it that use a wideband 02 sensor are the most accurate. They plug the 02 sensor in right next to your exhaust port(You will need to have an 02 bung welded to your pipes, normally a local shop will charge about $15-20 to do this)to get the most accurate readings, and feature a real time lcd display that allows the user to see in real time the actual afr that the bike is running. This will allow accurate tuning of the idle/pilot/slow jet, the needle at part throttle(while your riding, so an accurate load is presented)and the main jet at WOT. Plus your not constrained by time since your not getting charged by the hour. The unit will pay for itself in just half a day. And the beauty is you can take as long as you want to dial your carb in perfectly.

Some folks say carb farts are natural and ok. To some extent thats true, but thats becuase their carbs are "ballpark" tuned by feel normally. My carb never makes even the slightest hiccup. I havent had a carb fart of exhaust backfire since I have owned this devise. The bike runs super strong in ALL CONDITIONS, hot, cold, dry,humid etc.

And if you ever get tired of that race tuner software, do yourself a big favor and check out the S&S IST ignition system for the Sportsters. It pretty much garentees your bikes ignition advance will run perfectly under ALL riding conditions and loads. It comes with and/or uses your bikes sensors in combination to keep your ignition advanced as far as it will go before pinging/detonation. It is able to adjust for different temperatures and loads on the bike. It uses a cool head temp sensor and spark knock sensor to keep the bike dialed in perfectly under all conditions. I've run all the adjustable ignitions like the Crane, Daytona Twin-Tec,Dyna2000 etc, none of them compare to this module. And of course your rev limit can be adjusted as low as you want, all the way up to 7200rpms.

 

what he said
now finding the one to trust to set up the carb and not clean out yur wallet - any suggestions there MegaHDman?

 

Well if you have your own WEGO, then DIY. Otherwise I really can't make a suggestion since I dont even know where your or others are located. I know a smattering of decent tuners up and down the east coast but thats about it.