My son has a 2006 trx 90, i am pretty sure the front wheel bearings are bad (play in tire both on and off the ground) but there is a loud metalic "clunk" if i lift the front end and set it back down and push slightly down,it seems as though something is resetting into place.
Is this noise inherent to bad wheel bearings or do I need to check something else as well ? There is also about a half inch of play in the handlebars when not in motion.
Any and all help is greatly appreciated and thank you!

 

Yes a bad bearing makes mechanical sounds, Grap the wheel at 6 and 12oclock and if it wiggles its the bearing. Good news is there cheap and easy to change. Look on youtube many great vidoes show how to change them.

 

Could also be a tie rod or it could be a shock grommet is missing.

 

If you find play in the wheel, it can be handy to have an assistant wiggle things (both 12 and 6:00, and 9 and 3:00) while you put your hand on the ball joints, tie rod ends (inner and outer) and look around.

Wheel bearings are pretty easy to replace. Having a ball joint separator makes it easier. A cheap harbor freight one would be fine for your purpose.