SAFETY FIRST: Protective gloves and eyewear are recommended at this point.
If you have access to a high-speed wheel balancer designed for motorcycle wheels you can very quickly achieve accurate results. Alternatively, you may balance the wheels yourself using a truing stand. Never operate a vehicle with an out of balance wheel as you may lose control of the motorcycle. You should balance your wheels each time a tire is installed and you should check your wheel balance each time your wheel is removed or suspected of being out of balance.
To check your wheel balance place the complete wheel assembly in a truing stand. Spin the wheel until it stops on its own and mark the lowest spot with a piece of chalk or marker. Repeat this step several times to verify you have located the heaviest part of the wheel. A balanced wheel will not stop in the same spot so this test quickly reveals the problem area.
To balance the wheel you will want to fasten wheel weights on the opposite side of your chalk mark. Essentially, you will be adding weight to the lightest part of the rim to balance the wheel out. Repeat the spin test as mentioned above. You will want to add just enough weight to keep the wheel from stopping in the same position when it is rotated. Avoid over-weighting the wheel with too many weights.