I have the Spektrum DX6 ya know the Glitch Free one.

Well about a week ago my heli was Glitching, rotor speed up and down. Servos a lil jerky, I was like what the?????

It turned out to be a bad main motor.

On the new motor I ran it on 3v for a half hr to seat the brushes before installing it. Now it flys smooth as can be no glitches or weirdness. $9.99 and the problems all went away.

I think I may pick up a spare tomorrow just to keep one on hand.