You can read about the engines in the 4 stroke kits topic area, the engine on that is a Huasheng 142F. Very low maintenenance, fairly high reliability. I've built mine up last summer, and all you really need to do is change the oil occasionally, and make sure your bolts are tight like any machine. Tuning the valve lash is very simple and there's a great thread somewhere here on that process (only takes a few minutes). If they are asking $1500, that's a pretty good deal. With only 100 miles on it, they basically broke it in for you.