[nuz69]

The answer is in your post... You must not lubricate or try to clean this bearing, by doing this you risk to damage the shieling of the bearing and to put the dirt inside, which result in a balls damage and death of the bearing...
The bearing is dualshielded so it don't need lubrication or maintenance.
My CC 2200kV has already seen 213 batteries of 3000mAh, and the front bearing is still in perfect health, although I never try to dirt it off.
You will know it for the future.