I have a 2011 Motobecane Sprint road bike and i am having an issue with the headset.
I have watched the youtube.com videos on how to adjust it, but I think I may have bigger issues than that.

By grabbing the front brake and pushing the bike back and forth with my other hand I can heard the knocking in the headset, so I tighten the screw. I can tighten the screw so far that it binds the bearing in the headset and it still will knock by grabbing the front brake and pushing my bike back and forth again.

What is going on here?