Rebuilt 350 carb, lags/pops at 3k rpm

1972 CB350 late carb, rebuilt the carbs with the kit. Synced and idle screw setting is now close to completely screwed in. When driving if cruising low rpm high gear. 3 to 5k rpm in 3rd or 4th. When a small amount of throttle is applied engine pops and looses power like every third or so stroke. Tried resetting idle screw and doing the setting proceedure and the screw is again all the way screwed in. Rpm never falls. Help