82' KZ1000J BS34 #2 carb issue

Been chasing a rough running, not wanting to idle issue. Carbs rebuilt, coils, wires and plugs replaced, valves checked, new boots, carbs synced at this point.  Bike will not run without the idle adjustment turned all the way up. When I put my hand over the carb intakes 1, 3, and 4 bike will start to die. 2 it will speed up and I think that cylinder is the one backfiring. Bike seems to run better at higher rpm.

Have you checked compression?

Is there an open vacum line on #2 (fuel tap or emission valve/air box)

When you rebuilt the carbs, did you take them fully apart, soak the bodies and all the jets in carb dip, then install all new O-rings?  Did you verify that the pilot passages, both though the jets, and through the carb body up by the pilot screws, and the small orifices in the carb body under the pilot screws, were all open?  

Yes it is a little low in that cylinder but not gone.

I did dip them and thought I had them clean. Does it sound like something that would happen with a dirty idle circuit?