Actually, I've set up several of these gyros, and there is one other thing you might want to do first....

I noticed the gyro would do exactly what you mentioned if your revo mixing was enabled.

First, turn on the TX. Be sure to inhibit Revolutionary mixing (Don't just turn the rates to zero, you need to actually turn that function OFF). Set your rudder ATV's to their maximum limits (you'll adjust them in a minute, but for now turn them all the way up). Then, turn the 401 gyro to "heading hold OFF".


Now, turn on your RX.
Your gyro is in normal mode. At this point, your rudder trim lever should be centered. If the servo arm on the servo is not at 90 degrees, then you need to adjust it. The servo arm, and the tailrotor control arm should both be at 90 degrees. Ensure that the travel direction of the rudder stick and gyro are correct. For example, when you give a left rudder command, the tailrotor blades should move so that the leading edge of the blades moves opposite your command. So, if you give it a left command, the tailrotor blades will move right. (The leading edge, remember.) This is only true for a rotor head that moves clockwise.
Now, if your servo arm movement goes forward when you give a right rudder command, then, when you pick up the heli and move it quickly to the left, the servo arm should move in the same direction.

If this is all good, then you need to go ahead and switch the gyro to Heading Hold ON. The servo should move freely in both directions when you move the stick. If there is some slow movement of the arm, you can eliminate this by adding or subtracting some subtrim.

Now, for the ATV. At this point, the ATV is no longer an endpoint adjustment. It now regulates the speed at which the servo travels from one end to the next. Decrease the amount until you get a comfortable speed.

Hope this helps!