Bike looks good. As for the carbs, I'd stick with the keihins, I've always had good luck with them. Possible that they are tuned for higher altitudes if they are truly lean. Are you able to adjust the idle mixture screw or is it blocked off? Typically they blocking's can be removed with a drill and sheet screw. And the needles can be shimmed up as well. That's usually all they need with stock air and exhaust. What do the plugs look like?
