Swapped out the pilot jet for the 48 and set the screw at 2.5 and the decel pop cleared up. When riding slow, in off track conditions in low gears, seemingly at the transition from the pilot jet to the needle, the bike has a surging type stumble. It's just not a smooth transition. The speed at which I describe is in first gear as if you were going slow through someones yard as not to rip it up. Under race conditions, there is absolutely no problem. You can't notice any stumble or acceleration problem. Who else has this problem?