Motorcycle Repair: 1977 Honda CB400 stuck clutch, honda cb 400, honda cb400

Question
I have an old Honda CB 400 Supersport that I haven't ridden the past three months.  I didn't do any special storage while I wasn't riding, but the bike was in an enclosed shed during that time, sheltered from the weather.  When I went back to start riding the bike again, I found that the clutch was stuck and wouldn't disengage when I squeezed the lever.  I can switch the bike from neutral to first gear, but when I squeeze the clutch lever while the bike is in first, the bike won't roll.  This has happened before after periods of disuse, and I solved the problem by rolling the bike forward while in neutral and then slamming the bike into first gear to try to loosen the clutch.  I tried this technique this time, but it didn't seem to be working, and I didn't want to damage the bike by continuing to slam it like that.  I'd appreciate any advice about how to loosen the clutch.  Thanks!

Answer
I've had some luck running a bike around the block while holding the clutch in.  After a while, the heat and torque on the clutch will sometimes break things loose.  If that doesn't work, about the only thing left is to take it apart and unstick them by pulling the clutch pack apart.

Regards
Rich