It has been my experience that all of the center hubs on the stock head are slightly warped. I've gone through about 6 or 7 of them now, and every single one has been very slightly warped. It does cause a slight vibration at low head speed, but goes away completely at higher speeds. As a rule, I look at the skids and the battery wire that hangs below the heli when hovering. If those things aren't noticably shaking/vibrating, I call it 'good enuff'...

I also have had 2 main shaft/gears where the gear was not perfectly centered on the shaft. One was not too bad, but the other was very bad.


Using stock parts, I just don't think it's possible to get the rotor on a BCP perfectly smooth and balanced, but you can get it close enough that it will fly quite well.

Something else to look out for is head dampening. If it's too loose, then your blades will likely lose their tracking at a certain head speed. This can often cause vibration/wobbling itself. I currently have 2 shims behind my O-rings, and still have this problem slightly. I am going to add 1 more shim on each side tonight to hopefully get rid of it completely...