You have to remove the belt, seconday clutch, undo the track shaft nut. The track shaft nut is the one on the rh out side near the brake caliper. It is a prong style nut that is locked to the shaft in one spot. BDX sells a special socket to undo it. A hammer and a punch will work. It is suggested to replace this nut every time it is removed. Then there is a long bolt in the center of the track shaft that holds it to the diamond drive. It takes a 5/8 socket and about 15" of extension. Undo that and it can be very tight. Then go back to the lhs and remove the bolts that hold the diamond drive in. Pull the diamond drive out of the machine and change the oil while at this and inspect it. Go back to the rhs side and the track shaft will be seized in the brake rotor. Thread the prong nut back on 4 to5 threads and use a 2x4 or rubber hammer and hit till it starts to move. Once it moves take the nut off and pound it all the way out. Just don't damage the threads on the track shaft.
I hope this helps the brake rotor and diamond drive are usually semi seized to the track shaft other wise it is very easy. When you assemble it just put anti seize on the splines and it will be way easier next time.