BoBSLo

I bought a crashed f4i this past fall and I have been building it into a stunt bike all winter. The bike was bone stock before me besides a M4 slip on. I had to replace the front end but once I got it riding again I noticed it had a bad bog/hesitation in low rpms. When you really get on the bike from idle or try to clutch up it falls on its face. It bogs whenever power is needed. It idles perfect and runs well above 6k rpm. I started with a throttle body sync then fuel pressure regulator. Then put a fuel pump in it and new plugs. I just recently replaced the entire throttle body assembly and all hoses associated with the fuel system. Still no luck. Bike has clean air mod and second idle screw. The interesting part is that there is no bog in neutral when the bike is revved up but if you shift into 1st and pull the clutch in and rev up the bike the bog is there. It's a very strange symptom and i have no idea what could be causing this.

Open to any suggestions