There really should be not wobble as WillieBee said. However, I have ridden my old Suzuki when the rear wheels had at least a 1 inch wobble to them. The machine worked but it was not good for it and was probably putting too much stress onto the axle.

If you do change the bearings take the old one out and take it to a bearing shop and replace it. Last time I did this AC wanted like $90 per tire (inner, outter bearings and seals) the bearing shop had them for $35.

 

Check your wheel bearings usually wear fast if u use your atv on paved surface