the term would be over carbing.
to big of a carb could make your idle stink
but isnt a 21mm fully closed only like 2mm.
and isnt a 16mm fully closed only 2mm
whats the diffrence.
well the diffrence is when you gun it right off the line. you go from 2mm to 21mm in like half a second. and the motor is like oh fuck here we go and its racing to catch up starving your low end.
but on a 16mm set up. the carb goes from 2mm to 16mm and its ok with that its a little less. and it helps it get going
just ease on the throttle and give yourself a pedal or 2.