Didnt see if you mentioned it in the OP, or any of the later posts but DO NOT do this mod to your airbox on a carbed scooter. There is a breather tube that fits in that recess and it limits both the volume of the airflow as well as the turbulence to an extent. Minus that tube the carb will be sucking in too much air and you'll be running very lean, and develop the "lean jutters" where at certain points in the powerband it will hesitate and obviously if you keep it up you'll be damaging your engine.
I attempted to remove the breather, and open the passage a small amount and that was the result for me. I've since replaced the tube, and patched up the cuts. Back to normal operation. This serve more as a warning to the casual modder, or might attempt this and then wonder wtf happened.
Note again for the casual modder: the reason this will work on a fuel injected engine is the ECU will adjust the mixture (add or subtract fuel being injected) based on the air intake. A carb has no ability to do that hence the issue.
You may now return to your normally scheduled broadcast. Thank you.