These electric motors are very powerful. With the strength and rapidly moving chain someone can easily get caught up and spit out the other side of these things. It can literally rip your arm off or worst. Some safety things we have added are a kill switch in the front and another one in the rear by the motor. These big bright red buttons shut the whole system down when pressed. I am also having our welder put a metal cage around the motor and chain to prevent curious kids from sticking their hands in.
We then connected the chain from the sprocket on the motor to the main hub/sprocket on the axle. Remember you can change the size of either sprocket to create more torque or speed. Gear Ratio just like a ten speed bike.
We are opting for more torque. This vehicle will go 40 mph if we set the controller to unlimited and the gear ratio to favor speed. But with younger kids there is no need to go that fast. They will have just as much fun with more torque running through trails and small hills.
We also bought racing helmets. These are NOT bike helmets. Bike helmets will not protect you enough in a go kart crash. You need one that completely covers the head, face and chin.