When the axle assembly is installed with the bearings, collar, axle, and spacer the spacer shouldn't move because it will be sandwiched between the two collars when the axle nut is tightened. The spacer keeps the dimensions of the inner race of the bearings as they sit in the counter bore on each side of the wheel. When you take the axle assembly apart it'll float because to it's not sandwiched and without the axle passing through the center.
Check it out: Ronayers.com Microfiche Yamaha>Motorcycle>2006>FZS6V FZ6>FRONT WHEEL
Thanks for the info. It just looked odd when it was off of the bike. Good news is that removing dynabeads and haveing the wheels balanced at a shop cured 90% of my highspeed shake:thumbup: Now i can start to find the other 10%