KRC sells them. Downside is that they are very expensive, AND made for kart seat frames which are 1/2 inch. For some reason, after the three million Cat mini bikes I've restored, I always thought their frames were 7/8. "THIS" Cat frame is one inch. So I machined the clamp down, but it's thin, and a bit wobbly. I'll do something with a welder or with rubber later on to better secure it.
If I were a kid, I'd be plastering my growing collection of hot rod stickers all over the engine. :laugh: I think they'll go on my forehead to cover my third eye, once I stop making love with my new RTT exhaust and cool muffler flippy spring thingy.