Hard one to pin down. Mine does it when ridden hard or when I've made changes that may alter the air/fuel ratio (including changing the AFXIED setting). In my experience/opinion the ECU programming is pretty temperamental insofar as small variations whether it be riding style, air temp or minor mods can cause it to operate quite differently. I find some days it's very rough and prone to stalling for the first few minutes, other days not at all. While there are obviously rational causes it is certainly one of the "moodier" bikes I've had.
