Thanks. As soon as I turn it on and spin up it just hovers, so I don't think its overheating (though I realize the mods will help otherwise). I've trimmed it so it stays pretty stationary. But it doesn't "snap" to inputs like it used to. The lower rotor shifts when I use the right stick, but the heli barely moves in the direction and also drifts a little (the drifting isn't serious, and I could trim it out if the lower rotor was effective). It's kind of like a hot air balloon. If I can get it going in some direction, it takes a a little for the heli to slow down and change direction. I'm thinking it could be the motor, or the 4in1. Thanks for your help.