I had my dealer install a set of Vance & Hines headers with 4" Rinehart mufflers upon taking delivery of my 2011.5 SE Ultra. I was told that installing a tuner was not necessary as HD compensates for a certain percentage of air/fuel change when non-stock pipes are installed. Bike runs good, but everyone keeps telling me I definitely need to install a tuner as the bikes come lean from the factory anyway, and pipes only add to the lean condition...any opinions on whether to install a tuner, and if so, what kind?
ABSOLUTELY!! The ECM cannot compensate for the amount of extra air the motor is pumping now. If you just put the slip on mufflers on, it might be OK, but with the catless header pipe, it is now running very lean...too lean. The brand of tuner? TTS Mastertune, SERT...really, you need to first find a tuner, then talk to him about which device he prefers using. There are too many possible solutions to list them all in one thread, but if you look under the appropriate heading here, you'll read all you want to read. The bike will run better, and have more power, IF it's tuned properly. It will also run cooler.
If your dealer told you that it didn't need to be tuned, they don't have a clue as to how the ECM works on the bikes they sell. I'd find another dealer, if possible.