I had a crash, bent the flybar, replaced it.... tok apart the whole rotor head, no bent parts. The only thing that was rubbing was a ball link from the flybar controller, doesnt look like the linkage is bent though. WHY!!!! I recently replaced a main gear thats warped pretty bad. Other than that i dont know. AT low idle you can see a vibration in the head.i stripped everything sown to the main rotor shaft.Its fine too http://www.youtube.com/watch?v=zKSNgBFVqeo