Tom, its no big joke I can’t say that I have noticed a really big difference when the tires are balanced but here is how I do mine. Fronts are easy but the back are a bit trickier.
First you to your local hobbyshop and get some stick-on lead weights. They are used for balancing RC airplaces and are stamped in 1/4oz. increments and have 2 sided tape on one side.
If you look inside of the tire you need to find the spot where the two layers of rubber overlap. This is usually the heavy spot of the tire. I mark that spot and then mount the tire on the wheel. Now rotate the wheel in the tire so the valve stem is opposite the heavy spot.
Set the bead and put the tire on the kart and give it a bit of a spin. Usually the valve stem is enough to balance the wheel for me but if you do end up with a heavy spot take a weight and stick it to the inside of the wheel opposite the heavy spot. Spin the wheel again and repeat the last step as needed. I’ve never had to add more than one weight to get the wheel to balance.
Then I put a peice of tape over the weight to keep it form coming off. I use black electrical tape cuz my wheels are black but aluminum ductwork tape works great on polished wheels, its good and sticky and you cant really see it when its on.
I have hub mounted front wheels so I just use the hub and put my rears on the front to balance them. I think there are some tools available to balance the tire but im not sure who carries them.