Personally, I wouldn't worry about it - its a mini bike - no matter how hard you try, you likely will never eliminate the wobble. Manufacturers are a little relaxed with their tolerances and these chinese beasts are no different! As long as its not vibrating you off the bike and the tire is holding air.
You could break the bead and move the tire around the rim half way, changing its position, then seal the beads again. That may help some.
My little speed wobble doesn't bother me too much and it doesn't seem to cause the bike to rattle excessively at 40mph!!:thumbsup: