My best friend rides a YFZ 450 and is having a hard time with the dyno jet kit that he had bought. He has a White Bros. exhaust and a k+n air filter. Can anyone help with the jetting size? We are at sea level. In the dyno jet instructions it states that you should drill a hole for the correct mixture and place a big screw in the carb for adjustment. It doesnt sound right to me. Does anyone run dyno jet kits in there YFZ 450's?