Transform an old gas powered go kart into an electric go kart. Again , not really kid stuff but for the kids.
Go Kart Plans, Go Kart Frame Plans, Minibike, Kart Racing, Go Karts, Cart, Pedal Cars, Motorcycles, Welding
How to Create a Go Kart with a Lawnmower Engine. Though go-karts traditionally use horizontal mount engines, with a little modification, you can install a vertical shaft lawnmower engine to be the driving force behind your homemade racing.