JK, that is a nice gesture.
Robert C, the first mini bike I had as an adult- LOL, in my fifties actually was a Cat 250. It came with a 2.5 Briggs, and at 240 LBS, pulled me as fast as a small frame bike ought to be pulling anyone. No problem with going up the hill (paved) or accelerating. IMO, that Cat with this engine would be the ideal combination for kids under 14, with not a lot of riding experience. It isn't so fast and heavy that the scrub brake is overcame even with me on it.