How Fast Does a 125cc Dirt Bike Go? Average Maximum Speed

how fast does a 125cc dirt bike go

Dirt bikes, conventionally known as off-road motorbikes or motorcycles, are manufactured and decorated specially for off-road riding events. So here is the question- what do off-roads mean? Well, the roads that are not prepared for usual driving are called off-roads.

The roads we use for walking, running, or driving vehicles are on-roads. Sometimes people question is how fast does a 125cc dirt bike go? In this brief article, we tell it along with example and 7 actual factors that affecting dirt bike maximum speed.

But, for riders, like bike riders, there are some unconventional paths for riding. These are known as off-roads. Such as muddy, sandy, snowy, or rough surfaces.

So, dirt bikes are principally made for these off-roads riding purposes. As a result, these bikes are a bit changed from regular bikes. Dirt bikes are made with materials that are lighter and stronger than natural bike materials. You can ride a mountain using these bikes as well.

Besides, these are flexible and have long-travel suspension. More gears and strong breaks are added to dirt bikes so that rider can ride these bikes without much hassle.

So the maximum speed also depends on dirt bike engine power like 2 stroke and 4 stroke. However, 125cc dirt bike maximum speed could be 60 to 65 mph (104.61 km/h). Let’s discuss some actual factors that affecting dirt bike average speed.

Factors Affecting 125cc Dirt Bike Maximum Speed

Dirt bikes can be faster or less speedy. It will depend on the factors that affect the average top speed of a dirt bike. Some factors affect the speed of dirt biking. These are as follows.

Engine Size

how fast does a 125cc dirt bike go in km

The most important factor that affects dirt biking speed is engine size. In contrast, engine size is related to the seat heights of dirt bikes. Such as the height of a dirt bike seat starts from 18″ to 34″. In this case, 500cc to 150cc engines are perfect.

Besides, these dirt bikes are a great choice for kids, new riders, or inapt riders. While the seat height starts from 35″ to 38″, this will require 230cc to 450cc engines transposition. These dirt bikes are good for adults, experts, and experienced riders.

Therefore, your height, weight, and experience will affect the dirt bike engine. And all of these factors will affect the average speed of your dirt bike. If you are experienced, you can choose an expert’s dirt bike and go faster.

On the other hand, if you are a new rider, you should rather choose a kids’ dirt bike. You should keep your speed lower in this case. Therefore, your dirt bike’s engine will only matter in the case of getting more speed.

Don’t forget to checkout dirt bike theft prevention


The modification system of your dirt bike will affect the max speed as well. Highly-modified dirt bikes will allow you to go faster than lower-modified dirt bikes.

Hence, if you want to modify or customize your dirt bike, you will need two basic things. One is experienced, and the other is money. Let me clear these two for your betterment.

If you have enough or more than enough money, you can modify your dirt bike in any way you prefer. You won’t need to worry at all.

Just communicate with the best dirt bike manufacturer or company. So you will get your dream bike within the least possible time.

On the other hand, if you are experienced enough to know the parts of a dirt bike, you can amalgamate those parts from the best separate sources. It will cost you less than the others.

Once you add all of the parts, your dirt bike will be unique and stylish. Besides, you will be glad to ride your self-modified bike.

So, how you want to modify your dirt bike is upon you. But you have to know about the parts that you can change for modification.

Tires: You can upgrade the tires of your old or new dirt bike. It will help you to ride faster. Besides, you can change tires for achieving more experience. If you want to ride a mountain or give a tour, these changing tires will assist you to ride efficiently.

Bike Chain & Notch: Another modification of dirt bike can be the chain and cogs of your dirt bike. You can replace the notch and chain of your dirt bike. It will be cost-effective and give you more speed for riding.

Handguards to handlebars: When you go outside for riding off-road, you should be more cautious and protective to yourself. Though you wear helmet and gloves, these cannot protect your hands properly. So adding handguards on the handlebars will save you from getting much harm.

New Suspension: Bike suspension is very important as it can protect you from danger. Besides, the greater suspension will allow you to have much experience and comfort in the case of rock road riding. So you can alter the suspension by adding a better one in your lovely dirt bike.

Add Aftermarket Exhaust: Whether your bike is a new or an old one, you can add some exhaust to your bike. This is a famous modification system for bikers. An aftermarket exhaust can give your bike engine much power to go. Your bike will be smooth and comfortable besides covering more distance.

Therefore, you can follow any of these modification systems and modify your dirt bike fantastically. As a result, your speed will increase with your modified dirt bike.  

Weight of Tires

average max speed of 125cc dirt bike

The weight of your dirt bike tires is another essential factor in the case of dirt bike speed. You can cover more distance and raise much speed if your bike tires are weight-less and of the best quality.

On the other hand, you won’t be able to go faster is your dirt bike has weighty as well as poor-quality tires. Besides, the best quality tires will be light-weight and cost much than the poor-quality tires. So the choice is yours.  

Exhaust System

how fast does a 125cc dirt bike go

The exhaust system of dirt bikes is essential in the case of dirt bike highest speed. There are two types of exhaust systems: one is 2 stroke and the other is a 4 stroke exhaust system.

A 4 stroke exhaust system will cost much and these will be heavy. So you won’t be able to raise speed as you want. In contrast, a 2 stroke exhaust system will be cheaper, lightweight, and you can raise more speed adding this exhaust system.

Rider Weight 

Initially, weight does not matter if you are a new rider and want to ride for fun. But, if you are an expert bike rider and want to ride frequently, then your weight is an important thing to consider.

Medium weights are not a problem for riding dirt bikes. But, weights more than 320 lbs need greater suspension for riding properly and safely.

You should better modify your dirt bike with higher suspension (according to your weight). It will give you the benefit to cover much distance with smooth riding experience. You can ride mountains using these bikes as well.

While dirt bikes with lower suspension won’t be so great for mountain riding. Besides, you may have to face more problems because of lower suspension. Therefore, you should consult with bike experts before buying a new one. It will be a wise decision.

Rider Experience and Skills

Another factor that can affect dirt bike skills is the experience and skills of riders. The more you will ride your bike, the more your speed will increase.

Moreover, expert riders can go faster than beginners. So, the thing that is important than speed is riders’ safety. Experienced or beginner, speedy or less-speedy, whatever it is, you have to ride your bike with the utmost care and keep yourself safe from any kind of harm.

If you ride your bike at a higher speed and you feel comfortable and safe, then it is alright. But you should lower the speed if you feel uncomfortable or unsafe.

Stroke vs 4 Stroke Dirt Bikes

Another notable thing in the case of dirt bike speed is the strokes of a dirt bike. You won’t be able to cover the long distances within a short time if you have a two-stroke system added to your dirt bike. While a four-stroke system will allow you to cover more distance.

Generally, a four-stroke system generates more rotation at a minor RPM. While a two-stroke system generates more rotation at a major RPM.

How Long Does it Take to Reach Maximum Speed?

Usually, people frequently ask, how fast does a 125 cc dirt bike go? In a 125cc dirt bike can go up to 45 mph (72.42 km/h). But you can modify your dirt bike to cover around 65 mph (104.61 km/h).

Thus, you will need approximately an hour to reach maximum speed if you are experienced enough.

The Dangers of Speed

Speeds can be a great danger if you fail to keep a proper balance. In contrast, your balancing capability can allow you to upgrade your dirt bike speed. But safety is much important than speed. So, it is better if you keep your speed up to 40 miles per hour (64.37 km/h).

Final Notes

Therefore, a dirt bike is a fantastic choice for the riders who are skilled as well as like off-road riding. You can customize your dirt bike to get more speed. Dirt bikes with much power and higher seats can be harmful and less comfortable.

Also, you won’t get much speed in this case. Instead, lower seats with less power can be safe and comfortable for most of the riders. This will give you more speed as well. If you have enough experience, you can select a 125cc dirt bike and ride on any path as you wish.

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