Originally Posted by markjenn
If abrupt lower-end throttle response is the issue, the clutch switch mod makes it worse, not better. The main reason most folks like the mod is that it makes the throttle "snappier" and eliminates the slight bog the stock bike has off idle as you clutch away from a start.
There's a difference between faster throttle response you address and which is provided by the clutch mod, versus the off-idle stumble that the original question asked about. The switch mod took away the stumble on mine.
Tomatocity, to get through EPA certification, the stumble is a lean spot just off idle that is worse in some bikes than others.