Originally Posted by
onespeedbiker
I have an Ultegra 6500 headset in my parts box. As I'm looking at it, I am reminded that the cartridge bearings are pressed onto the upper and lower races. Perhaps one or both are not completely seated. You might want to tighten the the upper cone housing a little tighter than normal,to seat the bearings in the cones, then loosen and adjust as you normally would.
Those cartridges are a snug fit but are easily removable with your fingers. They are not spun in nearly permanantly like a Chris King headset. They would be owner replacable if you could find replacements.