so. before I do something dumb I m thinking that I should ask for some advice on here about building my boy a quad. this will be for flat track racing. what im thinking is a blaster frame, dirt bike engine, go kart rear tires. my main concern is an engine. I don't know much about dirt bike motors, what would be something good to start with? is there a big difference between an 80 and an 85? as builds go this is gonna be an average priced build.