IT's called page 17 of your 6EXH manual.
If you don't have the manual, then download it from here:http://manuals.hobbico.com/fut/6exh-manual.pdf
Pretty darn straight-forward. Make sure that you turn the receiver on with the gain select switch set to select AVCS (HH) mode. Otherwise the gyro will not work correctly.
Turn the DS switch ON, DELAY set to ZERO.
Make sure your transmitter makes the servo go the correct direction, then make sure the GYRO makes the servo go the correct direction. If you built your 450 correctly, right rudder stick must make the TR servo PULL the TR pushrod forward. If it doesn't, reverse the rudder channel in your transmitter. Then, pick up your heli and watch the TR servo as you turn the nose of the heli to the left. The servo must pull the TR pushrod forward. If it doesn't, then flip the NOR/REV switch on the GYRO.
With your rudder endpoints set to 100%, set the TRAVEL LIMIT to 100%, mount the ball link on your 9257 at a distance from center that will allow you to get at least +/- 45 degrees of servo travel without binding up the tail pitch slider at either end. Get this measurement close, then fine-tune the TRAVEL LIMIT pot so that you do not bind up the servo travel at either end of movement.
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