Dirt Bikes

How Fast Does A 125cc Dirt Bike Go| Complete Detail

Riding dirt bikes on the terrain has become the famous fun sport of all bikers who love exploring new places and enjoying their fun time with friends. Riders use dirt bikes to improve their stamina at many levels to enjoy racing in the dirt. Even youngsters who want to improve their leg strength ride dirt bikes like 125cc, which performs best for them, but they need to know how fast does a 125cc dirt bike go.

Short Answer

For a 125cc dirt bike speed, mainly, these bikes cover between 55 to 60 MPH. If we talk about the top speed of 125cc dirt bikes, it is recorded at around 100MPH. However, you should expect this speed from something other than regular 125cc dirt bike riders; expert riders only achieve this speed.

Today we are exploring the speed of a 125cc dirt bike, how we can achieve speed on this bike, and much more.

How Fast Does A 125cc Dirt Bike Go?

A dirt bike with a 125cc engine can achieve the highest speed from 55 to 60 MPH. But many riders need to gain expert dirt biking skills, so they don’t reach more than this; it becomes the highest speed of a 15 cc dirt bike.

But its speed is also recorded at 100mph with mastered skills in dirt bike riding. The speed of 125cc dirt bikes is slower than other big rivals of this model. However, this dirt bike’s model is best for riders with new beginnings in riding and intermediates. The Riders with riding techniques and expert skills in riding can speed it up with their techniques.

Factors that affect 125cc dirt bikes

Factors that affect 125cc dirt bikes

The speed of dirt bikes can vary depending on various factors influencing their average top speed.

  • Engine size
  • Modifications in the bike
  • Weight of tires
  • Exhaust system
  • Rider’s weight
  • Skills and experience of the rider
  • Type of stroke

Engine size

The engine size is a crucial factor that affects the speed of dirt biking. The seat height of a dirt bike is closely related to its engine size. Dirt bikes with seat heights ranging from 18″ to 34″ are equipped with engines ranging from 500cc to 150cc, suitable for different riders.

For kids, new riders, or less experienced riders, dirt bikes with seat heights from 35″ to 38″ require engines with a displacement of 230cc to 450cc, making them more suitable for adults and experienced riders.

Therefore, factors such as height, weight, and experience play a role in determining the engine size and, consequently, the average speed of a dirt bike. Experienced riders can opt for expert dirt bikes to achieve higher speeds, while new riders are advised to choose dirt bikes designed for kids and maintain lower speeds.


To people who want to know how fast does a 125cc dirt bike go, Modifications to a dirt bike can also impact the maximum speed of a 125cc dirt bike. Highly-modified dirt bikes offer higher speeds than those with fewer modifications. Customizing a dirt bike requires both experience and financial resources.

With sufficient funds, you can communicate with reputable dirt bike manufacturers or companies to create your dream bike. Alternatively, if you know the different parts of a dirt bike, you can source and combine those parts from various reliable suppliers, which can be a more cost-effective option.

Adding aftermarket parts, such as:

  • Upgraded tires
  • Improved bike chains and notches
  • Handguards
  • New suspensions
  • Aftermarket exhaust systems

These can enhance the speed and performance of a dirt bike. These modifications allow for smoother rides, increased power, and better handling, ultimately leading to higher speeds.

Tires weight

The weight of the tires on a dirt bike is another important factor influencing its speed. Lighter and high-quality tires enable riders to cover more distance and achieve higher speeds. Conversely, heavier and poor-quality tires hinder speed and performance. Opting for lighter, premium-quality tires can enhance a dirt bike’s overall performance and speed.

Exhaust system

The exhaust system of a dirt bike also plays a significant role in determining its top speed. There are two types of exhaust systems: 2-stroke and 4-stroke. While a 4-stroke exhaust system tends to be heavier and more expensive, a 2-stroke exhaust system is lighter, cheaper, and can contribute to higher speeds. The choice of exhaust system depends on personal preferences and budget constraints.

Rider’s weight

The rider’s weight is a factor, especially for experienced riders who frequently ride dirt bikes. Medium-weight riders typically don’t face significant issues, but riders weighing over 320 lbs require more excellent suspension to ensure proper and safe riding.

Higher suspension setups accommodate heavier riders, enabling them to cover longer distances comfortably. Lower suspension setups may not be suitable for mountain riding and can result in more difficulties. Seeking advice from bike experts before purchasing a dirt bike is recommended to make an informed decision based on individual weight and requirements.

Skills and experience of the rider

Skills and experience of the rider

Rider experience and skills are additional factors that affect dirt bike speed. With more experience, riders tend to ride faster. Expert riders can achieve higher speeds compared to beginners. However, prioritizing safety is paramount regardless of speed. Riders should always exercise caution, ride within their comfort zone, and prioritize their well-being.

Type of stroke

The type of stroke in a dirt bike is an essential factor regarding speed. If your dirt bike has a two-stroke system, you may need more time to cover long distances. On the other hand, a four-stroke system allows for more excellent distance coverage.

Generally, a four-stroke system produces more rotation at a lower RPM (revolutions per minute), whereas a two-stroke system generates more spin at a higher RPM.

Tricks to increase your 125cc dirt bike’s speed

Tricks to increase your 125cc dirt bike's speed

When it comes to knowing how fast does a 125cc dirt bike go, you also think about how to increase its speed.

Do require maintenance

The most crucial way that can help you to increase your 125cc dirt bike’s speed is by doing maintenance. For example, you can check the performance of your vehicle. If it needs to be changed, then change it. Even if your dirt bike doesn’t look like it needs to be upgraded, you should check it regularly. It will improve the performance of your dirt bike.

When you buy a dirt bike, it’s essential to carefully read and understand the rider manual provided by the manufacturer. This manual contains valuable information about operating the bike safely and effectively.

Additionally, you should tune up your motocross bike to ensure it is running at its best. If you notice anything unusual or have any concerns, it’s a good idea to seek help from a professional who can assist you with any necessary repairs or adjustments.

Air Filter upgradation

These filters play a role in removing the dirt that can occur on the carburetor during dirt bike riding, so you need to look at these also. These are the foam filters with two stages that help to protect your bike’s carburetor from dirt.

What will happen if you do not upgrade them? If you let the air filter consume the dust, your bike’s performance can be affected badly. The speed of the bike can be reduced.

To avoid disasters during dirt bike riding, you should install premium filters on your bike, which helps to prevent clog-ups and increase the performance of your bike. These premium filter upgradation can help your bike in uncontaminated airflow, which increases engine power and horsepower and gives the riders a comfortable and fantastic experience.

Use of High-quality fuel

This is the best trick to answer the question, how fast does a 125cc dirt bike go? The use of fuel that is good in quality can be the best trick to increase the speed of your dirt bike with a 125cc engine. While selecting the best oil for your 15 cc dirt bike is easy, you can get help here to choose the best fuel. But it would be best if you found the octane rating of your dirt bike first.

  • 87-Octane:

This fuel type blends 87% iso-octane and 14% n-heptane. It is vital because both compounds influence the fuel’s resistance to knocking, which is undesirable in an engine. Most dirt bike engines are designed to work well with this fuel blend, so you don’t have to worry about compatibility issues with your vehicle.

  • 90+ Octane:

For high-performance dirt bikes with smaller engine capacities, premium gasoline like 90+ Octane is recommended. These bikes need extra power, and the engine’s high compression ratio benefits from this fuel type. 90+ Octane also offers improved fuel ignition efficiency.

  • 85 Octane:

In areas with limited altitudes or specific geographical conditions, gas stations may offer 85-octane fuels. This is because higher altitudes have lower air density, which affects how fuel burns in the engine. Higher-octane options like 87 or 90+ might not be suitable in such cases. It’s essential to consider the air conditions in your area when choosing fuel.

  • Ethanol Blended:

Ethanol-free gasoline is the most common choice for dirt bikes and motorcycles. However, some governments have been promoting ethanol fuel for various reasons. Ethanol-blended fuels have less chemical power than standard gasoline, resulting in cleaner burns. The government provides subsidies to encourage the use of ethanol fuel.

Exhaust upgradation

Lastly, it’s essential to consider your exhaust system to know how fast does a 125cc dirt bike go. Upgrading it, or seeking professional help, is an affordable and straightforward way to boost your dirt bike’s speed.

Harmful fumes and gasses are efficiently removed by improving the exhaust system, making the bike lighter. This means you will have to exert less effort to move forward. Additionally, a smoother airflow through the engine enhances overall bike performance from start to finish.

Safety is important

Safety is important

When riding a 125cc dirt bike, prioritizing safety is crucial, regardless of speed. Take into account the following safety measures, especially if you’re a young or inexperienced rider:

Follow Speed Limits

While there may not be specific speed limits on muddy tracks or when riding downhill, it’s essential to consider your bike’s capabilities and ride within a safe speed range. However, when riding on public roads or downhill with normal road conditions, adhere to the posted speed limits for your safety.

Be Aware of Your Surroundings

Being familiar with your environment is vital for safety. Before getting on the bike, observe your surroundings. Take note of the terrain you’ll be riding on and study the route or any detours. This knowledge will better understand what to expect during your ride and help you mentally prepare.

Perform Bike Checkups

Before each ride, thoroughly inspect your dirt bike. Ensure that all components, from the engine to the seat, work correctly. If you identify any issues, address them promptly. Continuing riding is unsafe if you know of any problems that could compromise your safety.

Dress Appropriately for the Weather

Be prepared for various weather conditions. Choose clothing that is not too heavy, allowing you to move quickly on the dirt bike. Invest in protective gear such as knee pads and helmets to ensure your safety throughout the journey.


Is a 125cc dirt bike powerful?

Yes, a 125cc dirt bike can be considered powerful, though it is less potent than larger engine sizes.

How fast is 125cc in km/h?

The average top speed of a 125cc dirt bike is approximately 80 kilometers per hour.

Can a 125cc go 100 mph?

No, a 125cc dirt bike cannot reach a speed of 100 miles per hour (160 kilometers per hour).


In conclusion, if you are worried about how fast does a 125cc dirt bike go, the speed of a 125cc dirt bike can vary depending on several factors. The engine size significantly determines the bike’s top speed, with 125cc engines generally reaching around 80 km/h.

However, it’s important to note that the rider’s weight, experience, and modifications to the bike can also impact its speed. Safety should always precede speed, especially for young or inexperienced riders.

Adhering to speed limits, being aware of the surroundings, and regularly maintaining the bikes are essential for a safe and enjoyable riding experience. Ultimately, striking a balance between speed and safety is critical when operating a 125cc dirt bike.

Yousaf Khan

Yousaf Khan is an experienced biker with over 10 years of riding experience. He has a passion for motorcycles and has traveled extensively on his bike, covering thousands of miles across various terrains. Yousaf is well-versed in different types of biking, including adventure riding, touring, and off-roading. He is an active member of several local and national motorcycle clubs, promoting safety and responsible riding. Yousaf's dedication to the biker community extends beyond his own riding, as he regularly shares his insights and experiences with fellow bikers around the world. When he's not on the road, Yousaf enjoys spending time with his family and sharing his knowledge through this blog.

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