I know it's been a while since you posted this message, but I'm having exactly the same problem with a '90 Shadow 2.5 engine. Crankshaft sprocket won't come off, 5 bolt pattern, seal retainer blocking jawed pullers and I have destroyed my Harmonic puller bolts. I know the body of the sprocket has an internal shoulder that the shaft rests against but heat and force won't make it budge.
What did you do????????