Motorcycle Repair: idle problems 81 yamaha 400 special 11, yamaha 400, aircleaner

Question
81 yamaha 400 special 11
I have cleaned and cleaned the carbs, I have traced my idle problem back to the carbs. Valves good ignition good. I have taken the caps off now on the idle airmixture screws and still cant get my left cylinder to fire consistantly to idle right.  I beleive the mix in left cylinder is to lean because I can mist gasoline in the left aircleaner and it will fire correctly. After 1200 rpms the both cylinders fire fine all the way through the upper rpm range. It is just at 1200 rpm "idle" the left cylinder is not getting the proper fuel mix.  I heard I may be able to move my slide needle to adjust the mix but will this affect my idle or just mid and upper rpm range. Please help direct me on this if you will.  Thanks
Fred

Answer
Fred, thanks for the question. yes you can adjust your needle valve it shoudnt affect the idle because the spring inside will bring it back to the bottom of the jet when you release the throttle . try it it should be fine if you have any other problems i am here for you ok. P.S please dont forget to leave feed back on my answer. we volunteer our time but really enjoy feed-back . and nominations  if you feel so.

                             sincerely,
                       mitch kruszynsky