The proper way to adjust the idle mixture screw is to warm the bike up so the engine is up to temperature.  You want a fairly low idle speed for the adjustment.....this is the one time when you need the engine idle to be just a little bit slow so you can sense the changes best.  Don't get it Harley lump, lump, lump slow....but as close to the 1,000 rpm as you can.  Turn the idle mix screw in until you hear the engine begin to struggle or drop rpm.  Then turn the screw out until you hear the engine rpm increase and the engine runs smoother.  If you have to go out more than 2 turns you should increase the pilot jet size, and if you can turn the screw all the way in and the engine continues to run....the pilot jet is too big.

Know what..........I just found a really good video.
https://www.youtube.com/watch?v=zm5mB3R8Ucw

When you set the idle mixture and pilot jet size this way....you are jetting so the engine will "run" the way it  is supposed to.  Yes it may bang and pop when you close the throttle....but the engine is running the way it is supposed to run.  You can attempt to cut down on the popping and banging by intentionally making turning the mixture screw out another 1/8th or 1/4 turn to make the mixture a bit rich - but doing so will reduce your fuel mileage as the engine will be running a bit too rich when you are cruising down the road as slower speeds.  Once up to highway speeds you have the throttle open far enough that the effect of the idle mixture screw and pilot jet are minimized.

You can reduce the popping and banging by not closing the throttle completely as you shift of when you decelerate.  Just open the throttle a tiny amount, and you should hear the popping and banging go away.

Dave