Engine bogs down/stops during take off

[Armen444]

Alright so im in need of some dire help here. Ive read almost every carb thread here and a few other places and still have not heard of this problem. I know what every part on the carb does and still cannot figure this out, so i come to anyone with a suggestion that i have not tried yet. So here is the issue, bike idles fine, decent in mid and high range RPM, however between 1000-2500RPM the bike will not take off!!!! If you try and release the clutch and give her some gas the RPM shoots below 500. Heres what ive tried so far with little to no luck, obviously idle mixture screws, i have had them between 1.5-4 Turns out made little to no difference, I sprayed carb cleaner through the Pilot Air Jets and it shot out the other side no problem, ive played with the needles inside the slides (Had them in basically every position), Cleaned the crap out of the carbs by shooting carb cleaner through every orifice while disassembled. The Float Hight was adjusted to 11mm (slightly rich), the throttle bodies were also adjusted with dry method using precision bb's, ive played around with the timing recently but because of this issue its back to stock timing (no advance). I have a UNI multistage foam filter in the stock airbox, and i recently swapped the OEM exhaust system to a 4-1 Delkevic with the 18" silencer. Now, is it possible that i do not have enough flow restrictions on the bike due to the modifications? Reason for swapping the exhaust was that the OEM ones were rusted where the can meets the collector, so they were leaking a decent amount, which also made the bike run fairly wonky, because i tried sealing them temporarily and the bike ran amazing! Until the seal gave, and bike started acting up again. Thoughts people? Im out of ideas! The only thing i am deffinitely going to try next is going up a single size for every jet, this means #20 pilot jet, #107.5 for Cyl 1 and 4 and #105 for Cyl 2 and 3 main jets. I have ordered them already should be here next week. :ponder: :thumbdown: