i have a 07 90 also and it does not have adjustments for the needle. i bought a jet kit from Powroll, it came with three jets and a shim to put under the the clip thats in it. it really helped with the cold strarting. ive been told you can buy the little shim's or washer's at radio shack. if you get the time let me know how the new pipe works out. I'm buying one soon and curious as to how much better it does if any. thanks
06 700r raptor, 05 250 recon, ,07 trx90/hetrick pipe, pw 80 yamaha,07 xtreme125 typhoon with evos 140 motor, thanks to wife for posting pics!!!