I have a very similar problem
Originally Posted by geometrician
Could be the flywheel rotor bolts are loosening- look at TSB here
and dig around in HOW
counterbalancer is gear driven off a shaft so probably not!
. Bad vibes above 5000rpm on side-stand and when rolling. Other 06's are smooth in comparison, no vibes on side-stand. I checked my flywheel rotor bolts, none were loose when I tried to gently hand-loosen them. I didn't forcibly loosen and retorque as it requires specific loctite. As you say counterbalancer is gear driven so it can't jump due to low oil pressure/camchain tensioner issues, the woodruff key would have to fail and if that happened I expect you'd have bigger issues. When I get time I'm going to take it into my dealer, they're going to rip it apart and measure the crank runout. I've mostly been riding my 450 of late, too little time, too much depression to look at the 950, so it sits in pieces waiting for the trip to the dealer