I stumbled across these guys and I enjoyed their efforts. They basically build up karts for yard use and time trial them against each other in their backyard track.
I like this because it bridges the race world and the hobby world. We don’t get much yard kart action here, so I thought I’d share.
In this episode they put a tillotson 225R on and let her rip. This does seem to be a very torquey and quick 4-stroke.
They do more than karts too: