I gave up on my search for a replacement 1981 clutch but then found out that a 2 speed clutch from an 82 or 83 express would work. Found this clutch on ebay. My crank didn't have a key way for the little key that comes with this so I didn't use it. Works great. You barely notice the shift from first to second. Now I just need to get it to delay shifting until 20 mph or so.
It was almost as if Honda was planning to introduce the 2 speed clutch in the 81 model and then ran out of time and threw in a 1 speed clutch.