4500 Series carb has idling problem

Which Dominator(4500) carb and how new is it?
A lot of the newer Dominators have air valves in them around the center were the air cleaner stud is. The valve could be open to far letting too much air to bleed through, in other words a large vacuum leak.
On my older Dominator, I had to drill and tap holes in that area for air bleed jets so I could turn the idle screw down enough to close up the transition slot and get back to the idle circuit.