AVS2 tuning

With that cam & low-ish compression, you might need to enlarge the Idle Feed Restriction, which is the pinch at the bottom of the thin tube that hangs out the bottom of the pri boosters. Try 0.002" at a time. From memory, the 800 AVS has 1.75" t/bores. Pretty big. That means a small amount of throttle movement passes a lot of air.

Another thing to check if top end is lacking: check that the carb is getting WOT when you mash the pedal.
You wouldn't be the first person to be caught out with this....