The OEM steering bearings are ball bearings in a cheap plastic cage. Really poor choice of bearings for the purpose. Bearings of these type are typically used in high speed, low shock applications, which is just the opposite of what steering bearings are subjected to. If the cage has cracked, tightening is not going to help. Check out the link KawMan posted.
Also, I suggest using a higher weight fork oil, or changing to a mechanical solution to stiffen up the forks. A fork brace will help, too. There is too much flex in the forks in the OEM setup.