OK, may have to mess with your needles as well as your main jet too to get it right. I still say chances are the right pilot will be 45, doubt 48 like I run since there is more restriction than I have. Kills me how many people always say that the bike runs great. A lean bike will run better than a properly jetted one sometimes until the damage is done. Then it's too late. Our engines seem to be somewhat forgiving in that department though as I know some on here are very lean from what they have posted as their set up and the engines seem to be holding up. Seems more often than not people guess on the idle mixture too instead of a proper adjustment going by backfire on decel. If it is completely eliminated the jetting is wrong with a low restriction exhaust. Should be no real backfires but a kind of rumble so to speak, hard to explain the sound. Excessive backfiring could be an indication of a lean condition or an exhaust leak for most common causes. The properly adjusted idle mixture should be around 2 to 3 turns out much more than 3 and you should go up one pilot size. Since the pilot effects more than just idle you will need to compensate with the rest of your set up too if you want to get it right.
