Well, I can hardly believe it myself, but today I bit the bullet and pulled the brass plug out so I could adjust my PMS, and I can tell that at least some of the knock I've been hearing is due to my bike running waaaaay too lean. While I had the tank off I pulled the plugs and they were mostly white, although the right rear was less so.

Anyway, weather was crisp but dry today so out I went with the PMS turned 1/2 more than whatever it was. Warmed it all the way up, and I could tell that the knock was somewhat better, although I still had some backfiring. Came in twice more for some more adjustment and I'm hearing improvement.

Musky, I was recalling what you said to me and others here, that "these are noisy motors", and I can now think of it in those terms. The noise it was making was just too much, but I've got it under control enough that I can live with it. At this point it sounds like a gas powered motorcycle.

So, for anyone with a real knocker on their hands, I would try a richer PMS setting. Not a 100% cure, but just knowing that it improves the sound gives me hope.

One question: I'm at 4 turns out now, and I still can make it backfire if I really wind it up and chop the throttle. Is there a practical limit to how many turns I can have the PMS out. When does it fall out? haha.

Thanks to everyone for listening to my ramblings on this knock thing. I'm gonna fix it!