vibration, valve chatter - out of sync?

[Rothman]

First off I did do a search and found no helpfull info regarding what I'm asking. I am experiencing valve chatter and vibration from about 6k-8k RPM's. I have read that being out of sync could cause the vibration. Is that true? Could it also cause the valve chatter or am I just going to have to adjust the clearances? From idle up to 6k it runs great and from 8k up it's fine as well. I don't ride the bike hard at all but it seemed to be okay when I did a WOT run today. It's generally when I'm just driving normally that I notice it.

[Black_peter]

Carb synch should be all across the RPM range.
Unless someone knows of a specific Katana issue at that RPM range I would adjust the valves and sych it after that

[Rothman]

Well I guess I'll just start there then and see what comes of it. Thanks