RE: Eflite Blade CX
If your lower blades are tighter to turn than the uppers that is definitely gonna cause a problem. It may be tighter because the gear mesh is too tight. Try set the gear mesh and see if the blades spin a little more free than they are now. With 1 set of blades tight that means that motor is working harder than the other 1 and not spinning as fast which results in the heli spinning. Try to get them as close as possible.