There is one other way, and its a last ditch effort, but I've seen it done and it was successful. Acetylene torch. Hot flame quickly applied directly to the bolt(put snout of torch in the hole), and it will "pop" the bolt and pretty much vaporize it. The bolt has lower melting point than the crank, so you need to be quick about it. Don't ask me how I know this...but at this point what do you have to loose? The one time I witnessed this it was on a 95 SR that had a drill bit broke off in the bolt, and the threads of the crankshaft amazingly were unharmed after the procedure. The old guy that did it was experienced in this method and he said its dangerous for the threads, but it worked in that case.. Good Luck.