Most likely uneven brake pad deposits that feel just like a warped rotor, or a warped rotor, or sticking hardware.
IMO, get the manual:
Buellmods.com
Remove the rotor, and clean your stock rotor with scotchbrite, lube and torque the hardware as recommended, then replace the rotor making sure to follow the directions exactly. Re-bed the pads or even better, use the EBC HH pads for street use.