My 67 Bonne buzzed in harmonics. Front to back, up and down. Just like my Grandad's old vibrating recliner!! It had a great sound, (straight heaaders), and of course my girlfriend at the time, just loved the heck out of it. When I sold it, it was over between us.
The Enfield gets a little shaky around 30-35 mph, (buzzy mirrors), and after that, nothing, nice and smooth.
But, no chicks, either. Go figure.
I'm told I have to get an older ironhead for that now.
Steve