Ok here is a video of all the wheel bearing removal and install "secrets" Iv been using for years.
At 1.50 is how to move the spacer if you only heat one side at a time they will almost fallout.
Enjoy.
https://www.youtube.com/watch?v=y7GQI6Hh1bI
If it is a 03 or newer there is a spacer between the bearings on the sprocket side it MUST be put back in the correct way.
http://www.gasgasrider.org/forum/showthread.php?t=2566