I had an idling problem the same as this on both of my bikes. After cleaning the carbs I balanced them by eye with the spring loaded screw in the centre of the throttle slide shaft. After starting the bike it wasn`t running on one cylinder on idle. I then adjusted the slide balance screw whilst the engine was running, until I got an even idle from both cylinders. You`ll find you have to back off the idle adjuster as you get the non-running side firing. You should be able to achive an even idle this way.