When jetting your carb dial in the main jet first then work your way down to the mixture screw.

 1.  A good general way to find the best main jet is to put in a new plug, new fuel filter(if your bike has one), clean
      air filter, and go up a couple sizes till at top speed your bike has a slight (rich) miss then drop it down one size   
      (maybe two) till it runs smooth and pulls strong at top speed.

      If you have a miss it is generally rich, if your bike surges generally it means your bike is lean.

2. The needle is your mid-range so if you have a surging bike at cruise raise the needle if it is running rich lower
     the needle(the needle generally needs very little adjustment).

3. When you get the main jet and needle dialed in idle you bike as low as it will idle then turn your mixture screw
     in till it runs rough then back it back out till it has its smoothest idle. If its smoothest idle is past 3 turns out raise the 
     pilot jet one size and try it again. Your smooth idle should be at one to two turns out on the mixture screw.

     Always remember when you get you bike jetted that when the weather changes or you travel to a different    
     elevation you may need to fine tune your jetting for optimum performance. (This is from my experience with the  
     Mikuni carb.)