The rivots did not rub anything. They just gave some slop between the big plate and the back of the clutch baket. This gave it some room to move while rotating slow. I kinda know what you're saying about noisy kx's at idle. The two stroke's sound idling is weird. For one you have the exhaust sound, but you can also make out the cylinder and piston purring. And the they both seem to be doing a different pattern. Its the New Noises that are the bad ones. Sounds like something different than what I had. Mine made the noise bad at a slow idle, but was hardly noticeable at a fast idle and past that, or while in gear. Smart idea looking in the oil fill hole for the white collar, but I did have one break, but looked good until I finally removed it. 2 strokes are supposed to be a simple design, but it never seems easy to diagnose minor issues. you have to be ready to work on them, alot. Definately report what you find. You will likely save someone some trial and error with the same issue.