ok, I know the 500's are somewhat buzzy but mine is ridiculous. It seems to get worse as the bike starts to heat up (from cold start produces less vibes). My mirrors are rendered useless at stoplights, my hands get tingly, and my feet gets a (not-so-nice) massage on longer rides. My nuts and bolts are tight, did my chains and oil..

so the only thing I can think of would be carbs out of sync? or maybe the rubber thingie on the engine mounts are worn out?

My 500 is about to turn 1-human-year old in a couple of days and over 10,000-mile-age.

 

hahaha,
10,000 miles and have the valves been checked along with the cam tensioner? Yes a carb sync issue will cause a rough running machine, so will a dirty carb.