I don't know what the issues were with those bikes, but even DBW systems can be difficult if the engine is being pushed with regard to power output.
My point was that fixing\adjusting\experimenting throttle control issues is easier and more precise when done through a tune, as opposed to messing around with a physical linkage. You do need a good (great) tuner who knows what he's doing; maybe that was Yamaha's problem :icon_biggrin: