125cc Go Kart Top Speed: Speed, Acceleration, and Strokes [Overview]

Last Updated on August 5, 2023 by Pittalks

One of the most thrilling aspects of motorsport is, without a doubt, speed. The sensation of darting around a track at high speeds is a rush that’s hard to match. In the world of go-karting, the 125cc go kart is a popular choice for many enthusiasts, renowned for its impressive performance and speed capabilities. But how fast can it go? Let’s find out.

torque vs horsepower infographic

How Do You Define Speed? (Acceleration or Top Speed)

Before we delve into the specifics of a 125cc go-kart’s speed, it’s important to understand the distinction between acceleration and top speed.

Acceleration refers to how quickly a go-kart can increase its speed from a standstill, often measured by the time it takes to go from 0 to 60 mph. A go-kart with strong acceleration can quickly reach its top speed, giving it an edge in races, especially on tracks with many curves and corners.

On the other hand, top speed is the maximum speed that a go-kart can reach. This is often a crucial factor in drag races or tracks with long straightaways. A higher top speed can help a racer overtake their competition on these straight sections of the track.

How Fast is a 125cc Go Kart?

So, what’s the top speed of a 125cc go kart? On average, a 125cc go kart can reach a top speed of between 70 to 80 mph. This speed, however, is influenced by various factors, including the engine’s horsepower, the weight of the kart, and track conditions.

It’s also worth noting that the top speed can vary significantly between different types of 125cc go karts. For instance, a 125cc shifter kart is capable of reaching speeds up to 115 mph on particular tracks.

To better understand the various factors at play here, I suggest watching the video below. This video is a practical application where a 125cc go kart is being driven on the track, in a competitive setting, while also giving a visual of its current speed through GPS:

125cc 2-Stroke vs 125cc 4-Stroke Comparison

Engine TypeTop Speed Range (mph)Horsepower (hp)Torque (N-m)
2-StrokeUp to 75Around 30Around 20
4-Stroke25 to 356 to 9 Around 10
At least when used in go-karting, 125cc 2-stroke engines sure to pack a punch. I didn’t realize how much so, however, until seeing them compared back to back.

The type of engine in a 125cc go kart can also significantly impact its top speed and overall performance. The most common types are the 2-stroke and 4-stroke engines.

2-stroke engines are known for their high power output and impressive acceleration, making them a popular choice for racing applications. These engines can reach speeds up to 75 mph, given the correct conditions such as air temperature, gear ratio, track layout, and driver weight.

On the other hand, 4-stroke engines are typically used for recreational purposes. They are more durable and offer a gentler power delivery, making them suitable for novice drivers or younger kids. The top speed of a 4-stroke 125cc go kart usually falls within the range of 25 to 35 mph.

Here’s a comparison video that touches on these points, but also gives us an in-action perspective:

Estimated Horsepower and Torque Output for 125cc Karts

The horsepower of a 125cc go kart engine plays a significant role in determining its top speed. A higher horsepower implies a higher top speed. Typically, a 125cc 2-stroke engine can produce around 30 horsepower, while a 4-stroke engine generates between 6 to 9 horsepower.

In terms of torque, a 125cc 2-stroke engine can deliver around 20 Newton meters, while a 4-stroke engine produces around 10 Newton meters. Torque is crucial for acceleration and climbing hills, as it represents the engine’s pulling power.

Speed and Acceleration Factors

FactorImpact on SpeedImpact on Acceleration
Gear RatiosIncreaseDecrease

Now, lets go into depth about the several factors can influence the acceleration and top speed of a 125cc go kart:

Tuning (Fuel Mixture)

The tuning of the go-kart, particularly the fuel-to-air ratio, can have a significant impact on its performance. A lean mixture (more air, less fuel) can increase the power output and top speed but may cause the engine to overheat. On the other hand, a rich mixture (more fuel, less air) can improve engine cooling and durability but may reduce the power output and speed.

Gear Ratios (Gearing)

The gear ratio of the go-kart can also affect its speed and acceleration. A lower gear ratio (smaller gear) can improve acceleration but decrease top speed, while a higher gear ratio (larger gear) can increase top speed but slow down acceleration.

Weight (both driver and kart)

The weight of both the driver and the kart can significantly affect the go-kart’s speed and acceleration. A lighter kart can accelerate quicker and reach a higher top speed, while a heavier kart may struggle to reach its top speed quickly.

What’s Faster a 2-Stroke or 4-Stroke Go Kart?

In general, 2-stroke go karts are faster than 4-stroke go karts. This is mainly due to their higher power output and faster acceleration. However, 4-stroke go karts are more durable and easier to maintain, making them a popular choice for recreational use and younger drivers.

Is a 125cc Go Kart Fast?

Yes, a 125cc go kart is considered fast, especially when compared to karts with smaller engines. With a top speed of around 70 to 80 mph, a 125cc go kart offers a thrilling and fast-paced driving experience, making it a popular choice for both recreational and competitive karting.

Are All 125cc Go Karts Shifter Karts?

No, not all 125cc go karts are shifter karts. While 125cc shifter karts are a popular choice in competitive karting due to their high speed and performance, there are also 125cc karts designed for recreational use that do not feature a shifting mechanism.


In conclusion, the 125cc go kart offers an exciting blend of speed and power, making it a fantastic choice for karting enthusiasts of all skill levels. Whether you’re a beginner looking for a fun ride or a seasoned racer seeking a high-performance machine, the 125cc go kart won’t disappoint.

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