this one has me almost beat. Had the bottom end proffesionally done, crank seals new bearings etc.. I did the top end, fresh bore piston and rings all new gaskets, intake manifold is new and carb cleaned and float level set. Start and runs - however there is no affect by turning either idle or air fuel screw - which tells me there is an air leak. Had it running this afternoon and sprayed WD40 around base of cylinder and intake manifold = no bubbles. re checked all fasterners tight. Spark plug is dry black. so that tells me there is no air leak? and it is rich, tried raising the needle e clip - it did not like that. float is set at 14.45 mm (15 is stock) bike does not smoke - just whispers of it as it should. Mean cranks seals etc are sealed up. I am stumped. Maybe ignition related? bad stator? but that would in no way affect the carb screws having no affect.