I’ve never done it, but I own a balancer, came with my used kart. Of course it isn’t as fancy looking as the one pictured in the link below. My understanding after securing your tire/wheel/hub on the balancer you see if it wants to rotate to the heavy point. You use stick on weights to balance so it doesn’t just rotate to a heavy point. Sort of a basic version to your local tire shop.
Check at local shops first, JB might have something for sale or maybe IMI or the other kart shops. But you can also check out Rieken’s Racing @ http://out2win.com/catalog/tire_balancer.html
PRECISION TIRE BALANCER
More kart racers are discovering the advantages to be found in balancing their tires. Quicker lap times, longer tread life and smoother operation are just some of the benefits.
The new Burris precision tire balancer is a compact, rugged unit that comes complete with uprights containing free spinning bearings, 5/8″ shaft, an American pattern hub with all necessary hardware.
Part# BMC 7625B
Also Comet Kart also has them see:http://www.cometkartsales.com/store/tools/tiretool.htm