Sometimes what feels like a warped rotor is pad material build up on the rotor. This can happen when you change pad brands or compounds even within the same brand.
To fix you need a simple hone and a power drill - take the rotors off the wheel, hone both sides removing the built up pad material then re-install using loctitie on the rotor bolts.
Then bed in the new pads properly - (according to the manufacturer's recommendation)
I would say 8 out of 10 "warped rotor" complaints I've heard on motorcycles have been solved by this kind of maintenance.