Did you get the secondary off yet?
Start with what "blue" suggested by taking the 3 nuts that hold the helix off. Remove the helix, spring and outer sheave. Then you can wedge something behind the inner sheave (between frame and sheave) and use a long punch that won't damage the threads inside the jackshaft (where the secondary bolt goes) you can give it a sharp rap. Be sure the punch bottoms out in the jackshaft without touching the threads. I can't remember if I had to pull the belly pan loose on top or not in order to hit the punch. Once you are ready to hit the punch, you can apply heat as suggested above. The best penetrating oil for this seems to be Aero-Kroil (can get it online). I have tried everything I can find and this simply seems to be the best. I can't remember if I loosened the set screws on the jackshaft bearing or not. If it simply won't budge using reasonable taps, I would make sure you are not stressing any of the bearings (both ends) and give it some serious whacks.