no, but for optimal results i would. the stock ecu makes some adjustment to the fuel though, so you should be ok. just check the bike for noticable signs of being lean, if so add the cobra. i 'm waiting for the pcIII. lamont has added an airkit to go with his pipes and the cobra doesn't have the adjustments nessacary for his needs. if your just adding pipes the cobra will be fine and cheaper. guys around here are having good results with that combo. :bigthumbsup:
I think the only way the stock ECU could make any adjustment to the fuel is if we had the o2 sensors like the Euro/Aussie bikes do. our bikes run on a map that only gets altered with a programmer and the only other things that would affect the fueling would be engine coolant temp (cold start), manifold temp/press, throttle position and a couple of other things none of which will cause the ECU to change fueling on it's own. Drag style pipes have a tendency to make the bike run rich at mid range so only idle or top end would prolly lean out. I would say just stay out of running it to redline until you get a programmer and some dyno time with AF gas analyzer running during dyno runs to make sure you get it right. by the way the Dyno Jet PC111 is the only one that will let you take fuel away when programming which you will need with drag pipes and they are not out yet.