2003 KFX 80 NO Power

[Henschen ATV]

Hi. I am new to the forum. I have a 2003 kfx 80 and it has no power when there is a load on it especially on hills. It is not taking off like it should. No acceleration. I just had the motor rebuilt and this started to happen. Deleted oil injector and running 32:1 premix. I just put a new fuel petcock on also. I have cleaned the carb, new air filter, and newer belt. This thing runs great at idle and flat ground once it is up to speed. Thinking it was maybe the clutch I just did a clutch modification of taking the rear one down to 180 grams. I also took two rollers out of the front clutch. NO change. What else could it be or what have I done wrong?? Could it be Reeds? Clutch? Exhaust? Any help would be greatly appreciated.

Thanks