I did some work for Generac a while back. They manufacture that V-twin engine in-house. It's basically a motorcycle engine. I think Orange City Choppers or a similar show actually built a motorcycle with one.
It should be a good generator to do some mods to. If you ever want to do some sort of serial hybrid with a generator, you might want to go FULL-custom and have an engine power the wheels. At some point, it's not efficient to use an engine to make electricity to run a motor to spin the wheels. Instead, just use the engine to spin the wheels. That's one of the modes that the Chevy Volt works in. Check out the
RQRiley XR3. A friend of mine built frames for a pair of them!
I used a Generac RV propane generator as an experiment in my electric Geo Metro. In my experiments using a generator to power an electric car, I found out that you very quickly want the generator permanently mounted on the other side of a firewall, with a good muffler!