How to adjust Steering Stem Bearings ?
Do not over tighten the steering stem bearings, as this can cause the bike to weave.
tighten stem until all perceptable play is gone in the bearings, then give it another 1/2 turn.
or from the position that the stem just loosens up thats good.
Afterwatds tighten the stem set screw to avoid tourqu loss.
Sometimes you can use blue loctite.
On new bearings, overtighten the bearings somewhat to make sure everything is fully seated, or the stem will keep loosening up.
I Check mine every 100 miles or before every ride.