Generally, more experienced young dirt racers are likely to want more speed from their dirt bikes, and that’s where a 100cc engine comes in. But how fast does a 100cc dirt bike go?
A high-end 100cc dirt bike can go at a top speed of 45-65mph depending on the engine strength and maintenance, rider’s weight and experience, terrain, and suspension.
Note, nonetheless, that the engine stroke, which determines the dirt bike’s weight, also determines the dirt bike’s top speed. In that case, two-stroke engines, which generally weigh less, than 4-stroke engines, enjoy more power and speed.
To help you understand what I mean, I’ll discuss the engine stroke in detail. But before I do, let me take you through a few 100cc basics.
The Basics of 100cc Dirt Bikes
Essentially, a 100cc rating on a dirt bike means the bike has a 100 centimeters cubic engine. This displacement capacity offers the dirt bike the quality you need to compete at a motocross racing event.
Here are the dirt bike’s basics:
1. Rider’s Age
Essentially, kids from 9-10 years can ride a 100cc dirt bike, and even some adults, especially those of medium height (up to 162cm) and weighing under 160 pounds.
2. Seat Height
While you can use the age to determine if a given 100c dirt bike can fit you, you can only get a perfect size if you get the seat height correctly.
Here’s a table matching the rider’s height with the seat height:
| Rider’s Height | Seat Height |
| 140cm | 24-26” |
| 143cm | 26-31” |
| 157cm | 31-35” |
| 162cm | 33-36” |
| 172cm | 34-38” |
3. Horsepower and Transmission
A 100cc engine is powerful. Thus, you can count on it for sufficient horsepower, about 50HP or more. Essentially, the top speed is due to its impressive horsepower.
Another factor that determines its speed and ease of riding is the transmission system, which is mostly automatic. A few 100cc dirt bikes, however, have a manual transmission.
4. Engine Stroke
100cc dirt bikes feature either a 4-stroke or 2-stroke engine, impacting their top speed. Generally, a 4-stroke engine generates sufficient power for each two crank movements, eliminating jerks and promoting a smooth ride.
A 2-stroke engine, on the other hand, generates power for each single crank movement, making it more powerful. It’s, however, jerky, unlike a 4-stroke.
5. Speed
When it comes to the top speed, 100cc dirt bikes can average 45mph or more, depending on the type of engine stroke, among other factors.
6. Load Limit and Bike Weight
Most 100cc dirt bikes weigh 160-190 pounds and can bear up to 160 pounds. Overall, most of its weight is due to its engine. While comparing the engines, 4-stroke engines are heavier
Essentially, How Fast Does A 100cc Dirt Bike Go?
Top-end 100cc dirt bikes can register a top speed of 45-65mph, depending on the engine type (stroke), among other factors, which I’ll discuss next.
For now, it’s worth knowing that 2-stroke and 4-stroke 100cc dirt bikes register different top speeds.
How Fast Does A 100cc 2 Stroke Dirt Bike Go?
A 2-stroke 80cc dirt bike is more powerful than its 2-stroke equivalent under the same conditions. So it enjoys a higher speed limit. You can count on most 2-stroke 100cc dirt bikes to hit a maximum speed of 55-65mph.
How Fast Does A 100cc 4-Stroke Dirt Bike Go?
With a 4-stroke 80cc being slightly heavier than its 2-stroke equal, its speed is slightly lower. On average, 4-stroke 100cc dirt bikes can hit a 45-55mph top speed. There are, nevertheless, a few exceptions that run under this range or above it.
How Fast is a 100cc Dirt Bike Compared to Others?
When it comes to the displacement capacities of dirt bikes’ engines, the higher the capacity, the more powerful the engine and the speedier the dirt bike.
So, under the same conditions, a 100cc dirt bike outraces a 70cc, 65cc, and 40cc dirt bike while it’s slower than a 125cc, 250cc, and 450cc dirt bike.
Here’s a chart showing how a 100cc dirt bike compares to the rest. Use it to understand how fast dirt bikes go in general.
| CC Capacity | Potential Top Speed |
| 40cc | 15-22mph |
| 65cc | 30-45mph |
| 70cc | 40-50mph |
| 100cc | 45-65mph |
| 125cc | 45-75mph |
| 250cc | 70-85mph |
| 450cc | 80-90mph |
Factors Determining How Fast 100cc Dirt Bikes Go
Essentially, these factors determine how fast a 100cc dirt bike can go and hit top speed:
a) Engine Strength and Maintenance
A considerable part of a dirt bike’s top speed depends on its engine. Usually, the stronger its engine, the better it performs, and the faster it’s likely to go.
For that reason, it’s recommendable to service the engine regularly and preferably use high-octane fuel.
b) Rider’s Weight
Most 100cc dirt bikes can bear a maximum of 150-170 pounds. It all depends on their build quality and suspension.
In terms of speed, the lower the load, the likelier you are to ride faster. That means not only should you look at your weight but even the gears.
c) Rider Experience
It takes good bike handling skills and confidence to hit top speed with a 100cc dirt bike. So, the more experienced you are at racing with a dirt bike, the likelier you are to go faster and attain top speed.
d) Terrain
A 100c dirt bike can only attain its top speed if you ride it on suitable terrain. It doesn’t necessarily have to be smooth as dirt bikes are off-road intended.
However, the fewer the obstacles, dust, and gravel and the less steep the terrain, the faster you are likely to go.
e) Suspension
A suspension is an integral part of a dirt bike’s comfort, and it significantly determines how fast you can go. Generally, you are more likely to ride more quickly when your 100cc dirt bike feels comfortable, and a considerable part of that depends on the suspension.
So, the stronger the suspension, the more stable the dirt bike, and the faster you are likely to go.
How to Reach Top Speed with 100cc Dirt Bike
Honestly, reaching a 45-65mph top speed with a dirt bike is not easier. So, you have to do a few things that require effort.
Overall, these tips can help you attain top speed with a 100cc dirt bike:
- Use better gas
It’s vital that you use quality gas if you want your dirt bike’s engine to perform at an optimum level. So, instead of using lower octane (below octane-82), consider using a high-octane (octane-82 and above). That’ll improve the engine performance and speed in the long run.
- Oil up
Engine and chain lubrication not only protects against rust but improves their performance. Essentially, the more you lubricate the two, the better they perform and the faster you are likely to go.
Consider using Amsoil DB40QT-EA as it’s effective against friction and rusting.
- Upgrade the tires
Go for sleeker yet stronger tires as they allow you to ride smoothly and swifter. While at it, ensure you use the correct tire pressure (which I explain below).
- Use the correct tire pressure
If you want to avoid punctures and roll almost seamlessly with your 100cc dirt bike, you should always check the tire pressure. You should ensure the level is correct.
Overall, you should maintain the rear tire pressure at 6psi and the front at 8psi on a muddy road. But if the conditions are dry, you should keep the rear and front tire pressure 12 and 14 psi, respectively.
Who Makes the Fastest 100cc Dirt Bike?
Today, two of the fastest dirt bikes are by Kawasaki and Honda.
Japanese engine maker Kawasaki is famous for the Kawasaki KX100, which enjoys a potential top speed of 65mph under favorable dirt-racing conditions. Primarily, that’s owing to its top-end liquid-cooled 2-stroke engine.
On the other hand, Honda is known for the Honda CRF100, which the manufacturer discontinued in 2016. Like Kawasaki KX100, Honda CRF100 can attain a maximum speed of 65mph.
Most manufacturers have replaced 100cc dirt bikes with 125cc, 150cc, and 250cc options to promise more horsepower and speed.
Is 100cc Dirt Bike Safe?
From a speed perspective, anything that hits more than 35mph is pretty fast and thus possibly unsafe. But like any other bike, you can enhance the safety of your young rider by encouraging them to gear up.
Get them the best dirt-biking gear (Check on Amazon) to reduce the risk of an injury.
People Also Ask
1. How Fast Does A 100cc Pit Bike Go?
A well-maintained 100c pit bike can clock a top speed of 50-60mph under perfect conditions. Generally, you are likely to go faster when the weather and the track are favorable.
More importantly, it takes experience to hit top speed comfortably.
2. How Fast Does a Honda 100cc Dirt Bike Go?
Honda CRF100 can hit a top speed of 65mph, making it one of the fastest 100cc dirt bikes today. Note, however, that this bike comes in different generations with different potentials.
However, you are only likely to hit top speed when the dirt bike is in good condition.
3. What Does 100cc Stand for?
100cc stands for 100 cubic centimeters, which is the engine’s displacement capacity.
4. How Fast is a 100cc Mini Bike Go?
100cc mini dirt bikes are not very fast. The speediest options average a top speed of 23mph. That’s unlike top-end motocross options, which can register a top speed of 45mph and above.
5. How Strong Is 100cc Engine?
A 100cc dirt bike averages a horsepower of 5Hp or more. That’s sufficient to hit 45mph or more. You can thus count on this dirt bike for fast dirt racing.
6. Which Is the Best 100cc Dirt Bike?
Currently, two of the fastest and most top-end 100cc dirt bikes are the Kawasaki KX100 and Honda CRF100, which average a top speed of 65mph. It overall depends on the engine strength, riding conditions, and rider’s experience.
In Summation; How Fast Does A 100cc Dirt Bike Go?
Generally, a 100cc dirt bike is one of the fastest dirt bikes today, especially for younger adventurers. With the potential top speed being 45-65mph, this bike is undoubtedly an excellent motocross choice.
The best bit is that it accommodates younger kids and some medium-height and average-weight adults. So, it’s something worth having at home for adventures!