Originally Posted by
Shinkers
Sheldon himself said to leave it one ball short of full to prevent binding.
See here under 'overhaul':
Servicing Bicycle Headsets
Makes sense to me.
I'd also add that s withing from retainers to loose balls made a noticeable difference in headset adjustment for me. Much easier to set the preload correctly.
If the race is full of balls, and there is still a small amount of clearance between the balls, tell us how they can "bind".