1983 honda atc 200 strange rattle

[Hondajohnson]

just bought an 1983 200 cleaned the carb, cleaned out the gas tank put new rear brakes on! got it running starts first pull idles perfect but when you rev it up it has a bad vibration or bad chattering that sounds like its coming from the rear end but its hard to tell where exactly its coming from! dont own a mechanics stethoscope! it shifts perfect but chatters in neutral and in all the gears when its in high rpm! wondering if anybody else has had this issue? had centrifugal clutch apart looked good but cant take the other clutch off until i get the socket! clutch issue, exhaust, chain guard? any help would be great!

[350for350]

Maybe it's your cam chain or in the valves.