At maybe 3000-3500-4000 rpm's there's a resonant sound that comes and goes, definitely related to certain RPM's. I've reached down and tried to feel, I thought maybe the carbon belt covers might resonate, but haven't found what's making the noise.
Could the belts resonate like this if maybe the tension were off? Maybe something to do with the airbox? Airbox has been modified and is a little louder than stock.
Bike has 2500 miles, running great.