The air/fuel ratio will change after a good carb clean therefore requiring a sync.....unless the cleaning puts it back to where it should be.
Not exactly. It is balancing airflow thru the carbs by changing the slide height. Every cylinder sucks differently due to production imperfections, you are getting them real close. That is why it is not a uniform slide height you have to find, but individual heights
In either case as long as you don't disturb the slide needle locknuts you are golden. Inside your carbs when you take them off, under that smooth "top hat" will be the shaft that runs thru all four of the carbs. You will see an adjuster and locknut for the slide arm, don't undo them and you will be fine. All the other cleaning, as well as playing with your air mix screws won't affect sync
To final set your idle you gotta deal with it until you have been riding for a couple mins and have a good WARM engine. Unfortunately for you (not a big deal anyway) you don't have fast idle cams or carbs like more modern bikes that you can suit up while it warms up. Not a real problem but you gotta learn to ride the bike/deal with classics. Don't fiddle with the idle knob when it is cold so you can put your helmet on bc it won't run right when warm, it will die at stops. Try your idle at 1500~ and see how smooth it is there. As you dial in your air mix screws after cleaning everything you can obtain slightly lower idle. It isn't a harley tho, you aren't gonna be loping at 800
Nice bike, enjoy