The hub is not part of the rotor. The rotor looks like a slip on style but actually sits behind the hub and is held in place by the studs being pressed through the rotor and hub.
Here are a few pics of the D60 I built for my 250, hubs and rotors are the same but your calipers may use bolts rather than pins. You will need to remove the caliper then the lockout, remove the spindle nut and the hub then the rotor will slide off. You can then use a hammer to tap the studs out and if your lucky the rotor will fall off the hub. If your luck is like mine it will take a bit of prying to get them apart. You then press the studs through the rotor and into the hub and reinstall everything. You will need a special socket for the spindle nut, either 4 or 6 spline depending on if you have auto or manual lockouts. You will also need to set the preload on the bearings when you reinstall the spindle nuts. It would also be advisable to remove, clean and repack your bearings and if you are planning on ball joints, you will already have 90% of the stuff you need to remove off.