Well it has two shims. I took one out on both sides and the problem gets worst. As i was trying to take it back apart i broke the ball off of the paddle control frame. Going to get one today. I will let you know if that fixes the problem. Thanks for the info. Forgot to say that it had two shims per side. When i fisrt put it back together it didn't have any shims at all. It done the same thing. The tail boom bounces up and down. When i have it in a hover, I push the stick foward and back really fast and the thing starts bouncing. If i barely even breathe on the controls to move it around it does not do it quite as bad. I wish i could video this because i feel like i don't make any sense.