Have you split a crankcase without removing the rotor before?

I'm in the process of rebuilding my 81 cb650 and just started to split the case this morning. It is fully seperated but I cannot get it apart because my rotor is completely seized onto the crank. I have tried every trick in the book and am stuck. I have use the old rear axle trick, torch, pb blaster, hammer and pry bar to no avail. At this point I'm ready to go through four grinding discs to dry to cut it off. Please Help!!