I had some plastic tubes that fit well inside the bars, and put some "bird shot" in them, (not sure what gauge number), sealed the ends with electrical tape, and slipped this "cartridge" into the bars. I didn't fill it totally full, my theory being let the shot sort of vibrate around and resonate or whatever. I never had much buzz to start with but it seemed to help. I think I got more results out of reshimming and torquing the engine mount bolts. Also I have the heavy-type Throttlemeisters. What I don't seem to have now is buzz. Whatever works for you.