Here's an odd one. My dad bought this thing in '75. It's a '74 Aurenthetic. A company in Cali converted these gas powered minibikes to run off of two deep cycle 12V batteries. Throttle consists of a two way switch which partially turned, engages one battery fully, and turning the rest of the way engages the other one. Full 24V going to a 1HP motor, basically a starter motor.
I rebuilt it a few years ago just for fun and I couldn't believe how fast this thing was. Well, you know. Relatively speaking. But seriously, flat out I bet it would hit 35. Nephews got a big kick out of it.