Did you verify with k&t the needle and seat combo. I’m not well versed on mikuni carbs aside from smaller gassers. If that’s not rite it will push through . 7 mil cub by me at sea level 39keihin bored out. Tuned in at .1225dumps,.121 mains ,60 pilot Usually an E series needle. There’s also a lot of little things like is your power jet drilled out to far, angle of power jet, height into the carb bore . if your electronic check out start squeezing her down and read the plug , what’s your plug gap set at. , what plugs are you using. What were the ohm readings on your electronic components.