The bike runs like a fine clock 99% of the time. On throttle, off throttle, up and down the range, revving in neutral... the bike acts like it always has.Sounds to me like your throttle bodies are slightly out of sync. Does it rev fine? Does it stumble at all, or die when the throttle is snapped, then quickly released?
The only stumbling/stalling I've had is immediately after it cuts power in the upper rev range.