[brainsboy]

All engines need to be balanced when you do a rebuild. This is necessary to extend the life of your engine, it allows smoother operation, increase horse power, and improve gas mileage. Most machine shops will balance within a few grams, when I build all my motors I balance with in .5 grams. This reduces the centripetal force inside the motor. Centripetal force not to be confused with centrifical force causes bearing failure and wear. I bought a digital gram scale off ebay for about 70bucks, since then I check everything the machine shop does. I write down on paper all the piston, rod, bearing, and bolt weights before and after the machine shop does the work.

Ben