Have an 09 Vulcan Voyager. After the MCU upgrade last November the trottle and everything seemed Ok. On a former post I even commented on how smooth the throttle was then. Now like if someone flipped a switch, I can hold a steady throttle and the engine rpms fluctuate up and down. I'm still 100% stock. My dealer changed the air filter and plugs with no satisfaction. It's not as noticable on the road, or accelerating through the gears. It is noticable going through town with stop and go traffic when trying to hold constant rpms. I can feel surging. Just wonder if anyone has experienced this. Try gradually raising your rpms to 2500 and lock your wrist, do your rpms fuctuate up and down? Guessing it could be an elctronic throttle sensor problem or is this just another qwerk of the electonic throttle. Seems I would have noticed this previously having ridden 16,000 miles since new.