Your 4 brass screws on the sides of the carbs control AIR....turn them out to lean out your idle mix. You can get to about 2.5 turns out and then they are at their limit as to leaning you out.
You have a stock bike. 7/8ths +/- turns out on these should be sufficient. If your air plenum/airbox/filter allow too much air...or...your exhaust is unbaffled, giving less back pressure, this would warrant IMS setting greater than 7/8ths.
If they are 'stock'....something else is going on.
Your sync screws control carb vacuum. Dont adjust them unless you have a vac sync tool connected.
