Go-karts might be small, but they pack a mighty punch. With only 32 horsepower in your average Rotax kart, they can get to a top speed of 80 miles per hour in under 5 seconds. There’s no doubt that they are powerful vehicles, but you might still be asking how go-karts work.
Go-karts are incredibly simple vehicles, being essentially just 4 wheels with an engine. The 2-stroke engines use a carburetor to mix air and fuel in the engine, which turns the rear axle and moves the kart forward. The driver has control over the steering angle of the front 2 wheels.
What is most impressive about go-karts is their cornering ability, and this is where they truly beat the competition. Below, we go into detail about how go-karts function, and what all the parts are that allow go-karts to obtain their unique attributes.
How Do Go-Karts Run?
Go-karts run using a 2-stroke engine with a direct drive system that powers the rear axle, a spark plug, a carburetor, 2-stroke oil, and a clutch that connects to a chain that drives the rear axle. The driver works as the center of gravity, controlling it using a steering wheel and 2 pedals.
The engine is not extremely powerful, putting out just 32 horsepower. However, the kart weighs less than 200 lbs including the driver and a full tank of fuel. A kart’s high power-to-weight ratio is why they are so fast when accelerating and going down a straight.
The driver acts as the center of gravity because they are the heaviest object on the kart. This means that the driver’s seating position is incredibly important in how the kart handles. The driver has a steering wheel that controls the angle of the front wheels, allowing them to steer the kart left or right.
At the driver’s feet are 2 pedals. The throttle pedal on the right-hand side is connected to the engine through a throttle cable which lets more fuel into the combustion chamber. The left-hand side pedal is the brakes, which are connected to a brake chamber controlling a single brake disc on the rear axle – slowing the rear wheels down or even stopping them depending on brake pressure applied.
How Do Go-Kart Engines Work?
Go-kart engines work with an ignition system that starts by creating a spark using the spark plug. Fuel is pushed into the engine where it will mix with air, creating a small explosion that powers a single piston which moves the clutch, which moves the rear axle that drives the kart forward.
Karting is the most basic form of motorsport, and drivers are here to learn the basics of racing, mechanics, and motorsport. For this reason, the costs have to be kept low, so the engines need to be incredibly simple. Every engine is sealed after manufacturing, and there’s no way to open it up and get into the internals of the engine – unless, of course, you don’t plan on racing with the engine.
Go-kart engines have a small ignition system that is powered by a battery that is coupled to the side of the driver’s seat. The engine is started with a button just above the steering wheel which is used to create a spark using the spark plug. Once the engine is on, fuel will be pushed into the engine from the fuel tank through the carburetor.
The fuel going into the engine will mix with air, which then causes a miniature explosion inside the combustion chamber. This explosion moves a single piston inside the engine which in turn mores the clutch. The clutch connects to the rear axle with a chain which is used to drive the kart forward.
Do Go-Karts Have Gears?
Whether go-karts have gears or not depends on the type of go-kart you’re looking at. The most common go-karts, direct drive, do not have any gears. However, DD2 go-karts feature 2 gears, and shifter karts, the fastest go-karts out there, feature upwards of 6 gears in total.
The standard karts that you will most likely see are direct drive. This means that they do not have any “gears” as such, and only have a throttle and a brake pedal that the driver can use. These karts can only go forwards or stop.
Racing karts can come in different shapes and sizes, and the major classes are the junior and senior class karts. Senior karts are for drivers 15 years and older, whereas the junior class is for drivers between 10 and 15. The only difference is the senior class kart has a power band that will kick in anywhere above 4,000 RPM (although this can be adjusted) which acts as a turbo boost.
Aside from these 2 classes, drivers can choose from cadet karts (anywhere from 6 to 10 years old) and bambino class (3 years old and up). These karts are much smaller, and of course, much slower than their more senior counterparts.
DD2
The DD2 class is a step up from a senior class. However, it mostly comes down to personal preference as to which class a driver wants to compete in. Many drivers prefer to stick with the direct-drive senior class.
DD2 karts have 2 gears, and the gears are changed with a simple paddle shift on the back of the steering wheel. Pushing the right-hand side paddle down will shift the kart into second gear, and pushing the left-hand side paddle will shift the kart into first gear.
The DD2 karts are more complex and more expensive, which is why many drivers prefer to stick with the senior class kart rather than move up. Maintenance and tuning are both more difficult and more expensive.
DD2 karts are only slightly faster than the senior class at around 90 miles per hour (depending on the setup). However, they are considered to be “ultra-modern” karts because of the fact that they have electronic power valves, digital ignitions, and 4 braking discs rather than just 1 – therefore they require a different driving style.
Shifter Karts
If you ever want to experience the fastest kart possible you need to get your hands on a shifter kart. Shifter karts have 6-speed sequential gearboxes, and they can beat some modern-day supercars in a straight fight around a race track.
Shifter karts can hit around 140 mph (225 kph) in a straight line if they have the right setup and a long enough straight. It’s the 0-60 time that is even more impressive though, which it’s capable of doing in just under 3 seconds – similar to a Porsche 911 Turbo S, and a Lamborghini Huracan.
These karts are much more complex because they make use of a real motorcycle gearbox, which requires a lot more expertise, and a bigger budget. These might be more expensive, however, they are still incredibly popular all around the world.
The nature of the kart means that it’s the perfect tool for young drivers that are planning on racing cars in the near future. It’s a good way to get to grips with changing gears and how to downshift effectively to use engine braking when going into a corner.
Guide To The Parts Of A Go-Kart
1. Chassis
The first part we’re talking about is the chassis. The basic frame of the kart is crucial, and everything will be built onto this frame. When you see a kart frame with nothing on it, it looks incredibly basic. It’s a rectangular shape with some rims attached to it, and not much more.
There’s no suspension on a go-kart. You won’t even find small springs to dampen bumps on the tarmac. As a result, the ride of a go-kart is incredibly hard and the driver will feel every turn and bump in the road. This gives the driver incredible feedback through the steering wheel, which in turn helps them to develop their car control.
The chassis of the kart is incredibly important, both when it comes to safety and performance. In terms of safety, a chassis that is cracked or fractured may be on the verge of failing altogether, which would mean that the entire kart could literally fall apart. As such, chassis are meant to be updated each year, and a driver will not be allowed to race with a chassis if it’s too old.
The chassis can affect the handling of the kart as well. If the chassis is bent (from too much use or a previous accident) the driver may experience some trouble with handling. This could affect either right or left turns, or it could even affect the kart’s handling in a straight line.
2. Floor
The floor of a kart is essentially just a sheet of metal. However, it plays an important role in a kart. With the ride height of a go-kart being probably less than an inch, there’s a good chance that any bumps in the road will cause the floor to be scraped by the tarmac.
Without the floor in place, the driver’s feet would have nowhere to rest, and the kart simply would have no rigidity – meaning it would lose all of its cornering capabilities. The floor needs to be incredibly stiff for the chassis to properly flex while cornering.
The bottom of the floor can become damaged over time, and it will always be worn down whenever the kart is driven. However, the floor may need to be changed every now and then, especially if the damage to the bottom of the floor is becoming too much.
The floor is also prone to rust, especially if the kart is in a high humidity climate such as close to the coast. Karts in wet climates that experience a lot of rain also need to have a lot of maintenance and checks are done on the floor to ensure that it’s still strong.
3. Seat
The seat might seem like just a place for the driver to sit, however, it serves a much more important purpose than that. The driver is the heaviest object on the kart, so they are essentially in control of the center of gravity of the entire kart.
Taller and heavier drivers will need to move their seats in such a way that they sit lower in the kart. This will lower their center of gravity and make their kart more maneuverable and nimble. However, they can’t sit too low, otherwise, they might have their knees next to their ears.
Moreover, there are different types of seats out there. You may come across soft, medium, and hard seats. However, these have nothing to do with the comfort of the driver. In fact, they have more to do with the way that the kart handles, and they can make a big difference in the kart’s overall performance.
The seat, just like the floor, can change the way that the chassis flexes. Therefore changing the rigidity of the seat is one way to change how the kart behaves through the corners. There are many different settings to play around with, especially when used in conjunction with the position of the seat.
4. Rims & Tires
The rims and wheels are the contact patch between the kart and the tarmac. Starting off with the rims, they are incredibly small compared to a kart, but they’re also much more fragile. It’s incredibly easy to bend, chip, or damage a go-kart’s rim.
Behind the rims are what’s known as “spacers.” These can be moved from behind the rims to in front of the rims, and usually, they are simply put in place to create space between one object and another. However, in a kart, they’re a key setup tool used when adjusting the track width of the kart – altering its handling.
The tires used on karts are slick tires. These offer the most grip, and drivers will also use slick tires when they progress to larger racing cars. Slick tires have more grip than grooved tires because they have more rubber touching the tarmac (larger contact patch).
Tire pressures are a key part of karting, and it’s arguably one of the most sensitive setup features that can be used in karts. There’s a lot to tire pressures in karting, especially if you get down to a technical level where each tire gets an individual pressure based on how hard it works around the track.
5. Battery
The battery on a kart is extremely sensitive, and it doesn’t have a lot of power. They are much smaller than the battery you would find in your standard road car, and they have been designed this way to save as much weight as possible – they’re much lighter than car batteries.
The battery is only used to start the engine of the kart and to power any Mychron devices and sensors that have been attached to the kart (unless they are battery-powered). The battery issues the spark that gets the ignition going.
However, the downside with that is that it constantly needs to be charged. Karts don’t have alternators, and the battery needs to be disconnected after driving, put on charge, and reconnected to start the kart again.
6. Carburetor
The carburetor on a go-kart is very important. It’s responsible for slowly introducing air into the fuel lines while the fuel is on its way to the combustion chamber. Once in the combustion chamber, the fuel will be ignited and the engine will do its thing.
The carburetor of a kart engine is much more sensitive than those found on old cars. Kart carburetors are exposed to the elements, which means that they need much more maintenance and thorough cleaning than a usual carburetor would.
Inside the carburetor are jets and float needles. These are crucial when it comes to the setup of the art’s engine. The slightest change in air temperature or even air pressure can mean that the jetting setup needs to be changed entirely.
The jetting and needle setup are used to change the fuel mixture, or in other words, the amount of fuel that is mixing with the amount of air. Running the engine richer will mean that more fuel is used, and running the engine leaner will mean that less fuel is used – each is important based on weather conditions.
7. Steering
The steering on a kart is once again, very simplistic. There’s no power steering involved, and the driver will be feeling exactly what the front tires are doing on the tarmac. If the front tires go over a bump or a rumble strip, the driver will be feeling that through their steering wheel.
The steering wheel is connected to the steering column. The steering column goes down to the bottom of the kart into a pivot where two steering rods connect to the front “suspension”. The act of turning the steering wheel left or right, simply directs the front wheels in the same direction.
The steering on a kart can be brutal as a result. Many drivers begin to struggle if they are inexperienced or unfit due to the upper body strength required to keep the kart going at full pace. Drivers tend to have trouble with this when they first start out, and even when they are more experienced.
However, without power steering, drivers learn to experience the feedback they get from their kart as they drive it. On top of that, there is no way to implement any form of power steering into a kart without a heavy and expensive ECU of some sort being built into the kart.
8. Brakes
Unless you’re looking at DD2 or Shifter Karts (which have 4 brakes), go-karts only have 1 brake. The brake is found on the rear axle (which is the driving axle) and it’s made up of 1 brake disc and brake pads that clamp down on the disc to slow the axle down.
The brake pads are operated by a basic hydraulic system connected to the pedal underneath the driver’s left foot. The system is connected using a simple metallic rod. Pushing the brake pedal in moves the metallic rod forwards. This rod is connected to the brake fluid chamber.
With the rod moving forward, the brake fluid inside the braking chamber is compressed and pushed towards the brake pads, forcing them to clamp down onto the brake disc and slow the rear axle down.
Braking is very different from what you would experience in a road car (it’s the opposite in fact). The driver hits the brakes hard initially, slowly bleeding off the brakes as they approach the corner and get ready to turn in. This will generate the most stopping power possible.
9. Throttle
The go-kart’s throttle works in much the same way as any other vehicle would. The throttle pedal is connected to a cable that runs all the way into the carburetor. When the throttle is pushed down by the driver, the cable pulls on a spring which releases more fuel into the carburetor where it is then sent to the combustion chamber.
The fuel tank sits between the driver’s legs, and fuel lines are used to move the fuel from the tank to the carburetor. It’s a long way to travel, but power delivery is nearly instantaneous in a go-kart if you’ve got your carburetor and jetting set up right.
The throttle in a go-kart is not nearly aggressive enough for it to need traction control, but karts can still experience wheelspin when the rear tires lose their grip. This is rare though, especially when accelerating at full throttle from a standing start.
However, what the driver could experience is the engine bogging down when they apply too much throttle. This happens when too much fuel is sent into the combustion chamber, and there’s not enough air to ignite the fuel, which leads to the engine struggling to accelerate, especially out of slow corners – so throttle control is still crucial.
10. Air Filter Box
The air filter is the big black box next to the driver on the engine’s side. It might look like it doesn’t do much while the kart is running, but it’s actually got an incredibly important job that should not be overlooked.
The air filter will block out any impurities that are sucked into the kart’s engine. This same air needs to go into the carburetor and through to the combustion chamber. If anything other than air (such as rocks, grass, or dirt) goes through there you could be in trouble.
The air filter will prevent this from happening. It’s especially common in karting because of the fact that the karts are so low to the ground, and you may often experience stones or dirt being kicked up from karts ahead of you.
You should regularly clean your air filter box. Simply opening up the box and emptying all the dirt out of it will be sufficient, but there are more in-depth cleaning techniques that can also be used. Once you open up the box you’ll notice how much the air filter helps you out.
11. Radiator
The radiator is used to cool the engine down. Kart engines can reach high temperatures because they run at high levels of performance – sometimes up to 13,000 RPM. If the engine gets too hot it can begin to damage the internal components, and even seize up altogether.
The radiator is placed right next to the driver in the open air with a large surface area. This allows it to catch as much fresh, cool air as it possibly can while the art is driving. Inside the radiator, you could find either purified water or cooling liquid depending on the climate that you are driving in.
The radiator will cool this liquid down, and this liquid is then circulated through the engine. There’s a reasonably long scientific explanation as to why this happens, but the heat from the engine is then transferred to this cool liquid. This means the liquid becomes hot and the engine cools down.
The cooling pipes run throughout the engine which will help to cool different areas down. Maintaining your kart’s radiator and keeping it topped up with fresh water or cooling liquid is crucial when you’re driving your kart. It’s always a good idea to buy a Mychron with a temperature sensor to ensure that your engine never gets too hot.
12. Exhaust
The exhaust on a kart is used to expel gasses from the engine away from the kart, but there’s also a performance element to it. If the exhaust is damaged, rusted, or even if there is a small gap where air can escape at the exhaust manifold, the engine will be running at a lower level of performance.
Exhaust maintenance is more important than you might think, and you should always check your exhaust for any damage or rust. If your kart sounds louder than normal then there is likely a leak somewhere on your exhaust that you need to check out and fix.
On the other hand, you need to make sure that your exhaust is properly fastened too. The exhaust needs to be stiff (tightly fastened on the dampers) and moving with the chassis of the kart, otherwise, you could experience some instability in the kart through corners.
If the exhaust is loose, you’ll feel it bouncing around over bumps, which can cause damage to the exhaust or rip it loose from the exhaust manifold. The exhaust can cause further damage if it drops down on the rear axle of the kart.
13. Axle
The rear axle is the main driving force that your kart has. It’s connected to the engine through a sprocket and a chain that links up with the clutch (operated by the piston in the engine). The axle is what gets your kart moving forward, but it can also determine the handling of your kart. In fact, there are several set-up options that you have when it comes to the rear axle.
Just like with the seats, you get 3 different types of axles, soft, medium, and hard. Each of these axles has a different level of stiffness, which again, has an impact on how the chassis bends when cornering. In karts, you want to get the inside rear wheel to lift off the ground when cornering.
This will allow your kart to get the maximum amount of rotation around a corner. Changing the level of stiffness on the axle can help you to achieve this. Use an axle that’s too stiff though, and you’ll have too much grip which will ultimately slow you down (through hopping and sliding).
There’s more though, just like with the rims, the track width can be adjusted at the rear. It’s much easier to adjust the front track width compared to the rear, and it has the same outcome. However, you can control how much oversteer and understeer the kart has through the corners when you’re playing around with the track width.
14. Bumpers
Last but not least, go-karts have bumpers all around them. These are mainly used for safety reasons as they protect the driver from other karts around them. The rear bumper will cushion bumps from other karts behind them (bump drafting is a regular occurrence in karting).
The front bumper will also protect the front of the kart and the front wheels from impacts at the front. The front fender in front of the driver acts as somewhat of a shield to objects on track such as stones or any debris. Both of these are shaped as aerodynamically as possible to improve the kart’s shape.
The side bumpers are used to prevent wheels from making contact with one another. Any time 2 wheels touch each other there is always the risk of a kart being sent into the air, which is something that no one wants to see. These side bumpers help to keep wheels away from one another, and they prevent karts from making heavy side contact when going wheel to wheel.
Final Thoughts
Go-karts are simple machines that are built only with the utmost essential parts. They run similarly to how cars do, being powered by miniature explosions located inside the engine that move the piston. Standard models of go-karts don’t have gears, but more senior classes do.
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