Your problem sounds like my problem.
From idle, if I open it up all the way, the engine coughs and dies. If I open it up slowly and let the idle cliimb a bit, I can crank it open and it's fine.
Problem started after pulling the snorkel and baffle. I had to lower the clip 2 positions to keep the bike from popping at 1/2 throttle. I definetely noticed a gain in performance after doing this.
I pretty much elimiated the off-idle problem by messing with the mixture screw. I believe it is richer than stock (out farther), but not sure by how much. I set is as follows:
Set the idle screw for the slowest smooth idle you can get (this is proabably near the 1000RPM rec., but I don't have a tach).
Turn the mixture screw in until the idle gets rough, then back it out until it just gets smooth. I then went about 1/4 turn more for safe keeping (I'd rather be a but rich than lean).
THe problem isn't completely fixed. I think I need to go up a main and drop the needle to fix it or sure. I'll probably try that this weekend and will post my results.
BTW, you mentioned no change when pulling the snorkel and baffle. Is your bike popping more at mid throttle? Mine did. As I said, moveing the clip fixed that problem as well as delivered some performance gains. More air is only good if you have more gas to mix with it.
I suspect both are bikes are a bit lean off idle, and it may also be that the accel pump needs to be adjusted for the increased airflow. I do not have any experinece with those, so haven;t attempted messing with it...yet. If other fixes don't work, I may end up there.
Mag