+ 1 on what GPFan said, and it might be lean in more than just the pilot and needle jet circuits, it really depends on what RPM rangs are affected, in what gears - mph doesn't really tell us anything at all.
Popping on deceleration is usually a sign of the pilot circuit being lean, like GPFan already mentioned, but the reason I speculate that you might be running lean in you main circuits also, is that you said you're running 126 for mains, and have a K&N filter AND a full exhaust - the Factory Pro jet kit instructions call for you to use the included 138 mains when running a K&N filter (stock is 135)... for me, with the K&N filter, and just a slip-on pipe, I had to go up to 142 mains, to get the fuel needed, and I unleashed the engine's demons at that point - it rocketed to redline in the first 4 gears lickety-split - after adding the Two Bros. racing header, my mains so far seem ok (though I really should toy with one size higher, to see if there are any more gains), I raised the needles another position, and turned out the mixture screws another 1/2 turn each for a total of 2.5 turns out... every bike, even of the same make/year/model, has it's subtle differences, one to the next, but with both of us running K&N's and race headers, and the difference being 126 to 142 is quite a spread, so, food for thought anyway, unless you really ARE going to sell the thing! If you do, go fuel injected for your next bike - it's A LOT simpler to tune!!

 

that explains why the mains were 138's before i changed them... but the mixture was at 1.5 turns. next time i rip it down ill try the 138 again and go to 3rd clip position on the needles and go to 2.5 turns and see if it helps at all. seems to do it from 3rd gear on. its just weird because it runs fine for a lil bit at first. i was kind of wondering if the coil packs were the cause. i guess i wont know till i play with the carbs again!