Mine had some vibes around that range when I got it, but not as bad as some I gather.
My solution was to fill the bars with lead shot, which you can get from an ammunition reloading supply, or cutting open
lots of #6 shotgun shells!
I also machined custom bar ends out of brass that are mucho heavier than the stock ones, and look sweet to boot.
Together, these two things have almost eliminated the buzz at all rpms.
I've also heard that gel grips help, and of course gloves, which you always wear anyway, right?
Shiny Side up!
Elmojo