Reply to Andrew:
Great find.
I have found the clutch plates must swell slightly on a dry clutch machine like yours that hasn't been used for a long period.
If you cant put up with it loosen the adjustment slightly. You will be tightening the adjustment after a bit of use..
You need to know how to adjust and lubricate the clutch.
Clutch adjustment and lubrication is part of a operators daily routine.
When using these dry clutch machines, although the book says not to , I keep a squirt bottle of thin oil on the machine to squirt oil on the over center linkage pins. . This makes clutch use a lot easier and smoother.
As per Andrew saying oil the linkages on the clutch it helps but from experience that is not the end of the story.
As a kid learning close up tillage of walnut trees with a 4r D6, no protection from limbs the clutch needed to working well as it was life and death. Besides greasing the old guy instructing said a little oil on the clutch linkage helps.Well one day I cannot get in disengaged, so shut it down and went for the old guy.
"Have you been oiling like I show you", yes of course. "When was the last time you washed it with gas", he forget to tell me that part. If you start getting a build up of dirt,splash some gas and some compressed air to clean and start over with oil. I am not familiar with the changes but if your clutch is enclosed rather than out in the open it will not get caked in dirt near as fast.
This was very dusty conditions and the 4r and 5r had no cover to keep dust off as the newer 8u and 9u have with the same clutch.