Cause of problem.
A - Stock tires....unless you're riding on glacially smooth asphalt all the time, rip them puppies off and THROW THEM AWAY, allright ?
They're crap, they'll always BE crap - buy some Cheng Shins.
B - Kickstand draggin, which happens in a lotta Tomos's yeah, jut go shell out for the sidestand, if you ride a lot, and do lay-over turns, it's well worth it.
C - Underinflation, check yer pressure.
D - Rear wheel bearings/axle loose, rare, but it happens, check that and all your suspension connects as well.
E - Poor road conditions, that one being obvious, especially in "the strip"...that bein the area in the center of a lane where all the gas, grease, and oil seems to land...worse at intersections but watch it nonetheless.
F - Balls bigger than Brain, and don't think I am baggin ya on that one, cause you'd have to travel pretty far to find someone worse than me...
Anyhow, mopeds do have their limitations, and when you like to push the envelope...well, prepare to pay the postage, yannow ?
Hope alla that helps some,