Fresh bore has nothing to do with jetting. Did it run like this before top end?
Did you do a leakdown test and re-torque the head/jugs?
Clean the carbs puss clean and that doesn't mean a quick douche, take everything apart. Be sure petcock, carb vents, and tank vent are clean/open. What do the plugs look like? Is air filter clean? No mouse nests in silencers?
Quick check is when it gets to the "flat" spot is pull choke out half way. If it gets better you're lean, worse to rich, this ALL depends on everything else being ok.