How Do Go-Kart Motors Work?

Overview of Go-Kart Motors

Go-karts are small, four-wheeled vehicles used for racing or off-road recreation. Most recreational go-karts run on 125 cc two-stroke engines that are powered by gasoline. These types of motors allow recreational go-karts to reach speeds of 115 mph. Some go-karts used in professional racing have larger engines and can reach higher speeds, although amusement parks and other public recreational centers typically place a gubernator on go-kart motors that prevent the carts from going faster than 15 to 25 mph.

Mechanics of Go-Kart Motors

Go-kart motors are internal combustion engines in which gasoline is sprayed into a combustion chamber. The resulting combustion creates power that drives the motor’s piston. A two-stroke motor completes an entire combustion cycle in only two piston movements rather than four, as is the case with most automobile engines. Gasoline enters the combustion chamber through a fuel intake line; the flow of gasoline is regulated by a reed valve. The motor’s spark plug causes the fuel to combust, which drives the piston in the crank case. Byproducts of the combustion process exit the motor through an exhaust outlet, which funnels the gases out through the go-kart’s tailpipe. The piston inside a typical go-kart motor displaces 125 cc of air, making the motor rather powerful given the size of an average go-kart.

The Go-Kart Drive Train

The motor is attached to the go-kart’s powertrain, which consists of the drive shaft attached to the cart’s main axle. As the piston moves up and down, it rotates a large crank that's attached to the drive shaft via a gear. As the gear rotates, it spins the drive shaft, which in turn spins the go-kart’s axle. The spinning of the drive shaft transfers torque from the motor’s piston to the axle and ultimately to the go-kart’s wheels. Most go-karts have rear-wheel drive systems, which means that the drive shaft is attached to the go-kart’s rear axle. The rear axle provides power to the cart’s rear tires, which propel the cart forward.