I just changed to a spectrum dx 7....my mx 450 set up fine but Im having trouble with my mx 400 set up....everything checks out right but when I spool up....the heli spins...I would normally just reverse the rudder servo and all would be fine...no deal here....its a telebee gyro and I have also tried the reverse switch on the gyro...no change....I know its working ....When I move the heli, the gyro responds wth servo movement...Im sure its a mental bonehead block but sure could use some help..dave

check if your belt is slipping, my mx400 tail goes to the right because the pulley is worn out.