Just play with your air screws. And Idle screws. Once i get a cheap digital camera i can show you step by step. I got 28mm keihins.
On the right side of each carb there is 1 black screw with a spring on them. These are your idle screws. To tell if they are "even" check your lifters, throttle plates, whatever you want to call them, make sure they are even. You turn them out (screws) lowers the plates(decreasing the idle), turning them in (screws) lifts the plates (increasing the idle). Turn each screw on each carb at equal intervals.
It may be hard to get to the screw on the left side carb. I used a screwdriver like a mini socket wrench type thing.
Then you may have to adjust your throttle response to get the "bog" out in your bottom end. Facing the left side of the Banshee on the left carb. On the bottom right you will see a screw that is below flush. Turn them all the way in. DO NOT TORUE!!!!! Start the bike and set your low throttle response. Turn them OUT a half turn. on each carb. Keep doing this until your response is right!!!
I hope dis helps