Anyone into go karts?

my dad built us a cart when I was a kid. My uncle has a machine shop and built us the hubs for the sprocket (Yamaha dt-1) and brake rotor (Honda cb 360) to fit our 1" axle. It had wheel hubs from a garden tiller along with the tractor tread tires. We used a 250 dt-1 engine at first and it was a blast, when my buddy and I "upgraded" it with an engine from a Yamaha xs 650 things got out of hand, those cast iron wheel hubs would just explode, and those engines vibrate real bad- wasn't as much fun then