Yeah , the longer bars act as a harmonic balancer , like the "dumbell" balancers on a power line . Shorter bars and smaller rotating mass ( wheels and tires ) exacerbate the affect . Mine wobbles 40% of the time , lots of theories out there , but no definative solutions . New tires seem to be a valid remedy . Adding weight to the outer extremities of the bars will help , i.e. heavier , taller mirrors , heavier chrome grips , end weights , ect .
P.S. Next time you have the grips off , try an internal bar end weight , resin - lead - resin plug affair .
