There are actually several different things you can do to make a go-kart go faster. Some of the things you can do are simple and inexpensive, and others can involve a little time and a little outlay of cash. Some of the tricks for making a go-kart go faster involve such things as disconnecting the engine's governor, designed to keep the engine's rpm down to a safe level. Once you have disabled the engine's governor, you run the risk of overrevving the engine and reducing its lifespan. The following are different ways you can increase the speed of a go-kart.
Install larger-diameter tires on the go-kart, especially on the rear. Increasing the diameter of the tires means that each revolution of the tire pushes the go-kart further than it would go with smaller tires. Increasing the diameter of the tires by 1 to 2 inches can dramatically improve the speed of the go-kart.
Re-gear the kart. Install a smaller sprocket (or a sprocket with fewer teeth) on the drive axle or a larger sprocket on the engine output. In this way, the axle will make more revolutions each time the engine makes one revolution, causing the go-kart to go faster. Use some caution and do not overdo this option because this will cause your engine to have to work harder when first getting your go-kart to move and could result in the engine stalling out.
Dismantle the engine's governor. This is a device that is specifically designed to reduce the engine's rpm as a way of protecting the engine. Once the governor is dismantled, the engine will run faster. Dismantling the governor is a major undertaking that generally requires taking the engine apart and is not recommended. If you manage to remove the governor, listen carefully to the sound of the engine once you have dismantled the governor and try not to run it full throttle too much of the time or you may reduce the life of the engine.
Install a larger engine with greater horsepower. Again, this is a major undertaking and requires you to remove the old engine and drop in a new one. This can be complicated by the fact that a larger engine may not fit into the space that held the original engine. Unless you have a well-equipped workshop, this option is not recommended.
Add 91 percent rubbing alcohol to your gas tank. A 50/50 mixture of alcohol and gasoline should increase your go-kart's horsepower and improve the speed.
Install a nitrous-oxide kit. Adding nitrous oxide (laughing gas) to your fuel system can increase horsepower and speed.
Make sure the air filter is clean.
Removing or dismantling the governor can increase your speed but you risk over-revving the engine and greatly reducing the engine's life.