Hi Phil and Dan,
I still have the suspect Centa unit on the shelf. I took a hard look at splines on the portion that bolts to the crankshaft and they appear to be uniform (no obvious wear that would indicate rotational wear from rocking side to side due to the nut loosening up. The noise it made at idle was very much like a dry clutch Ducati makes but 4 or 5 times louder. The unit was installed at 7k miles and failed at 12k miles, the replacement is still quiet after an additional 13k miles.
In retrospect, had I known what the repair would cost and the apparent condition of the failed parts, I would have towed it home, pulled the motor, applied liberal amounts of loctite and motored on.
Best,
Roland
