Aerox still running rich on full throttle

Hi all.....got my scooter idling fine & running much better with 80 main jet in.Im running 17.5 carb with standard air filter engine is AC cooled with 70 kit on.Its also running fine on full throttle up on the stand but soon as i actually sit on it, its struggling plug is black as the ace of spades aswell,cant really go much lower on the jet is suppose,however i have not had tune coming out of air filter with box on the end ( boost bottle ive been told ) would this make a difference ? Also needs a mountain of revvs ( AT least half throttle or 3 quarters b4 she thinks about moving ) idle screw at the min is about 2 n half out,mixture screw about 2.........might i need new rollers / clutch etc......cheerd

 

This sounds like an air leak, I was under the impression I had no air leaks but found one underneath between the crankcase in a very hard to reach place. Spraying carb cleaner around that area soon answered the same symptoms I was experiencing as you. This was after fitting a new clutch, ht lead, cdi, belt, carb an a whole host f different jets etc when all it was is an air leak