I talked with Vivian, the owner of the SuperMax company that grinds off the teeth on a worn sprocket and then rebuilds the teeth with neoprene. They have been at this for a long time. I described what we have been going through and she immediately went to the aluminum composition of the rear sprocket as the only culprit. To her, these are all off-the-shelf replacement sprockets with a dubious heritage. They do have one thing in common: low price in comparison to sprockets made of tougher aluminum or steel. The alloys become expensive and the harder they are the more expense you will have machining them.
She quoted me ~$535 not including shipping. It takes time and they do small batches. She did add that they had been in touch with one of their first customers who has passed 150,000 miles on his belt driven sprocket and it is still quiet and looks almost new.
Alignment is still critical as well as tension. Too tight is a definite no-no. The belt still needs to track reasonably centered in order to not damage the belt by having the sides fray.
I have arranged for my dealer to ship my old sprocket back to me. He needed it to fight for the warranty on my behalf. Again. I am going to bite the bullet and do this as, even with my new rear sprocket (the third!) having been deep anodized, it has already started the small chirping noises in less than 1,000 miles so it is only a matter of time. As of next week my warranty dries up like a California reservoir during the summer.
I, too, have heard rumors of steel sprockets in Morgan's future. A little late for me...
