Put your bike up on a stand. Grab the forks at the front wheel axle and try to move it "fore and aft". If there is any play at all you need to either tighten the bearings or replace them.
To tighten them leave the bike on the stand. Remove the handle bars. Loosen the allen head bolts holding the tree cover. Remove the big nut in the center of the cover, and carefully remove the cover. You'll see the 2 nuts used to hole the tripple tree on. Remove the "lock nut". Tighten the bottom nut to the specified torque.....OR tighten the nut till the forks don't "fall" to either side from any position, but don't get it too tight. There is controvery about the top "jamb nut". Mama Yama says reinstall the rubber washer then put the jamb nut on so the grooves align with the lower nut. Some of the guys on here say leave the rubber washer out and "jamb" the jamb nut tight on the lock nut. Either way the grooves must be lined up to get the "keeper" back on properly.
If, after tightening them, you feel any "rough" spots it's time for replacement.
If the movement is smooth then put the cover back on. Tighten the big nut in the center to 92 ft-lbs. Tighten pinch bolts (hex
head bolts). Reinstall handlebars and go for a ride.
I'm sure if I missed something someone will chime in.