PUll the front caliper and the caliper mounting bracket off and hang the caliper with a piece of wire , don,t let it hang on the brake hose , and smack the back side of the rotor with a brass hammer and rotate around a bit and hit it again, it is most likely just rusted on at the center hub, these are basically floating rotors , when you put the new ones on be sure and use antisieze around the perimiter of the center hole and they won,t stick so tight next time , just smack it back and forth if your going to install new ones doesn,t matter if you bang it up , if your are going to reuse it, brass won,t tear it up as bad Jerry