On the iron the rotor slides off after removing the crank bolt. I imagine on the AVL it is pressed on but by looking at the Hitchcocks parts book it also has a woodruff key (red arrow) that keeps it from spinning on the shaft. You may be able to walk it off using a flat wrecking bar inserted underneath, a rubber mallet and a 2x4 as a prop.
I used the wrecking bar technique to remove my drive sprocket. Being careful and moving the motor, sorta a tap, move, tap, move type activity.
I also made a spacer to put under the clutch center (using a big socket and wood) and used the center plate with the three bolts (no springs) to pull it off the spline. You will need to walk the clutch and drive sprocket off at the same time as the chain really does not have all that much flex in it.
A nice rubber mallet is your friend.