Check your head clearing. I had one that came with only one shim. If you're running with 20% nitro is fine but with 30% you should add an aditional shim.
Also, this engine likes to be broken in at the track. I spent half gallon braking -in the engine just running around the track going from low to mid speed.
Another tip, don't try to set-up the needles as you were setting a Nova Rossi carb, it is very different. It usually likes a rich low end. Don't touch the mid needle!, I run mine at 4 turns in the low needle 4 1/2 in the top needle. Use Josh Cyrul's tunning guide. Once you've set up the low speed needle right, the rest is easy.