[47topless]

The two surfaces, clutch disk and flywheel, are not mating properly. Before taking the clutch apart, I would at least try to "mill" the disk by riding, (smoking) the clutch for a few seconds. That would also burn off any "foreign" materials on either surface. No harm to try this before going to all the work of accessing the clutch.
As suggested above, I would check the motor mounts first.
Good luck.