Slowly you need to work the clutch off. WD40 or any of the other penetrating oils you like need to get in the key slot on the crank and between the crank and the clutch. I don't recall any set screws anchoring that clutch to the crank. The key way is giving you some of the issues. Let the oils do their job and start working the clutch off. Rushing this job will give you additional headaches.
Maybe some one out here has a nice short cut.