Modify Animation clip curve values

Hi, I'm kind of new to working with animations in Unity, but here's the question. I have a human model imported into Unity, it has its own animation. I can open the Animation Window and look at the animation clip for the right leg, in there I can modify every keyframe of the animation curve. All I need to modify is the Rotation.y values from that animation clip. Is this possible to be done via a script? Thanks ;)