New TE610 had very noticeable head shake at highway speeds 65-70mph. Adjusted preload and rear rebound damping with some improvement, but still occasional head shake. Now with about 400 miles on the bike, the head shake is all but gone. High speed stability seems improved. Now thinking part of the issue may have been with the tires and now with some wear things have settled in. Running 25 psi front and rear for the street. Will drop down for offroad riding. Motosportz steering damper on order and hoping that will help both on the street and in the dirt. Love the motor and the overall agility of the bike. Need to get some miles on it!