Rob...try to get something threaded to weld on there. Slide hammers and crankshafts are not good allies. Perhaps fabricate a custom solid stub that fits the length to the crankshaft bottom (narrow to clear the threads) and weld a nut to whats left of the fixed sheave. Use the heat from welding to your advantage and quickly zap some pressure to a bolt up against the stub while its warm from welding. If you have no luck with the heat...grease helps in making a hydraulic press if you fill the end of the crank up. So long as your puller setup traps the grease when you start cranking on it...it will help in getting it to pop. Good luck...I have seen some real messes trying to pop clutches and flywheels from tapered shafts. Try not to bang on it too much with heavy stuff...a crank problem could easily result. If it comes to it...you may have to take a dremel and cut a few precision slices...and then get it to split open with a sharp chisel.
PS without a way to hold the clutch...you will have to use an impact gun...which is kind of your last resort in this kind of situation. Im sure you know...but DONT try to hold the crank in any way from the pull start side or with a piston stop...you will twist the crank for sure.
