Bogging if I let off throttle

[slobanshee]

I have a bog/stumble that I can not get lined out. 10mil cub on alky, lectrons, shearer oof's, +12 swinger. It's not bogging on the hit at all. If I stay wot it pulls great. But if it starts wheelieing and I have to feather/blip/roll out of the throttle any it falls on its face and bogs bad for 15-20ft and then it'll pick back up and does fine. Iv been up and down on the needle, tried 3*,5*,9* timing and all kinds of tires. I'm out of ideas. Please help