Throwing in my 2 cents. I have really never had a bad engine from any of the top manufacturers. There are many good 100cc class engines, at this time it is really hard not to choose the BME 115. Lighter than the rest and more power to boot. Balancing in not a problem if proper location of components are used. It will spin a Mejz 28x10 at 6800 give or take on stock mufflers once run in.