Nick, grab one of the heavy duty pullers from Gordon/ilbikes, those things are amazing. Chewbacca recently pulled his rotor that was stuck bad too, and he used the same puller. Don't waste money on the ebay pullers. I have one that I can loan you, just let me know and it will be on its way. You'll need to the engine either in a big stand, or the crank in a huge vice to get it off. You could also try to get some rust off with a wire wheel on a drill motor.