How Fast Does a 50cc Dirt Bike Go?
If you’re looking into 50cc dirt bikes, chances are you’re wondering how fast they really go.
Maybe you’re buying a first bike for your child, or just curious how this beginner-friendly engine size stacks up. Speed is important, but with 50cc bikes, safety, size, and rider experience matter just as much. This guide breaks it all down so you know what to expect before anyone twists the throttle.
What Is a 50cc Dirt Bike?
A 50cc dirt bike is a small off-road motorcycle with an engine displacement of 50 cubic centimeters. That may sound tiny compared to a 250cc motorcycle or a full-sized road bike, but this engine size is intentionally built for beginners, especially kids who are just starting out.
Most 50cc dirt bikes are lightweight, low to the ground, and easy to control. They typically use automatic or semi-automatic transmissions, so young riders don’t have to worry about shifting gears while learning. Many of these bikes also come with speed limiters or throttle restrictors to keep top speeds in check during early rides.
You’ll find both two-stroke and four-stroke versions in this category. A two-stroke model tends to be peppier and a little faster out of the gate, while a four-stroke version offers smoother acceleration and better fuel efficiency.
These bikes are great for off-road adventures in the backyard, on trails, or at the track. In some cases, they can even be modified for street-legal use with proper equipment and registration.
How Fast Does a 50cc Dirt Bike Go?
Most 50cc dirt bikes can reach top speeds between 25 and 40 mph, which translates to roughly 40 to 65 km/h. That might not sound fast compared to a 250cc motorcycle or sport bikes built for high speeds, but for a small, lightweight bike designed for kids, it’s plenty.
Speed varies by engine type and whether the bike is stock or modified. Two-stroke 50cc bikes like the KTM 50 SX or Yamaha PW50 tend to be a bit quicker off the line and can hit the higher end of that speed range. Four-stroke models are usually slightly slower but offer smoother, more controlled power delivery, which is something many parents prefer.
Here’s a general breakdown of top speeds for popular 50cc models:
KTM 50 SX (2-stroke): ~65 km/h (40 mph)
Yamaha PW50 (2-stroke): ~45–50 km/h (28–31 mph)
Honda CRF50F (4-stroke): ~40–48 km/h (25–30 mph)
Suzuki DR-Z50 (4-stroke): ~45 km/h (28 mph)
Electric models (like Razor MX500): ~24–32 km/h (15–20 mph)
It’s also worth noting that many 50cc dirt bikes come with speed restrictors installed by the manufacturer. These can limit maximum speed to around 25 mph (40 km/h) to help new riders build confidence before riding at full power.
Speed Comparison: 50cc vs 125cc vs 250cc vs 600cc
Curious how fast different engine sizes can really go? This quick comparison shows the average and top speeds of four popular types of dirt bikes and motorcycles, perfect for beginners, weekend riders, and speed lovers alike.
What Affects the Speed of a 50cc Dirt Bike?
Even though 50cc dirt bikes fall into the same engine class, their top speed can vary quite a bit. A few key factors play a role in how fast these smaller motorbikes can actually go in real-world conditions.
Rider Weight and Size
Lighter riders will naturally see higher speeds. Since 50cc bikes are designed for younger or smaller riders, putting an adult or heavier rider on one can reduce performance significantly and affect the bike’s aerodynamics.
Engine Type: Two-Stroke vs Four-Stroke
Two-stroke engines generally produce more power for their size, which is why a two-stroke 50cc dirt bike tends to be faster than a four-stroke model. However, four-stroke engines are more predictable, making them a better fit for beginners or those focused more on durability and control.
Terrain and Surface
Riding on flat, packed dirt allows a bike to reach its maximum speed more easily. But if the terrain is soft, sandy, rocky, or uphill, speed can drop by 5 to 10 km/h or more.
Gearing and Throttle Limiting
Many 50cc bikes come with throttle limiters, also known as governors, to help parents control speed. These devices can be adjusted or removed as the rider gains confidence. Gearing also affects how quickly the bike accelerates vs. how fast it can go at full throttle.
Maintenance and Tuning
A well-tuned bike with a clean air filter, fresh oil, and properly inflated tires will always perform better. Poor maintenance can cut top speed and reduce reliability, even on short rides or light off-road adventures.
Can You Make a 50cc Dirt Bike Go Faster?
Yes, you can make a 50cc dirt bike go faster, but it depends on how far you want to take it and who the rider is. Many of these bikes are intentionally designed to cap speed for safety, especially when they’re built for young riders.
Remove the Speed Restrictor
The simplest way to increase speed is by adjusting or removing the throttle limiter. Most 50cc dirt bikes come with a factory-installed restrictor to keep the maximum speed around 40 km/h. Once removed or loosened, some bikes can hit 50–65 km/h.
Upgrade the Exhaust and Intake
Swapping out the stock exhaust system for a performance version improves airflow and can give the engine more power. Pairing that with a high-flow air filter helps the engine breathe better, which often results in a small bump in horsepower.
Rejetting or ECU Tuning
On carbureted models, rejetting the carburetor to match new airflow can make a noticeable difference. For fuel-injected bikes (including some electric or newer 50cc models), ECU tuning or performance modules can unlock higher rpms and more aggressive throttle response.
Tire Pressure and Size
Something as simple as using the right tire pressure or switching to tires with less rolling resistance can also increase speed slightly, especially on hard-packed dirt or flat roads.
Important Safety Notes
While modifying your 50cc motorcycle for high speeds can be fun, it’s not always recommended for young or new riders. More speed means more risk. If you’re considering making your 50cc street-legal or planning to use it for commuting, check local laws and speed limits before modifying anything.
Who Should Ride a 50cc Dirt Bike?
A 50cc dirt bike is the perfect starter bike for younger riders, especially those between 4 and 7 years old. These bikes are small, lightweight, and designed with safety in mind, making them an ideal introduction to off-road riding.
Ideal for Young Beginners
Most 50cc dirt bikes have a low seat height, easy-to-use controls, and smooth power delivery. That makes them a great match for kids who are just learning to balance, brake, and steer. Models like the Honda CRF50F and Yamaha PW50 are favorites among parents thanks to their durability and reliable four-stroke engines.
Why Parents Choose Them
Aside from the manageable size, many 50cc bikes include parental controls like throttle limiters and kill switches. These features let parents adjust how much power the bike can deliver, keeping top speed in check as young riders build confidence.
Better Than Jumping Straight to a 125cc
While some families consider starting with a 125cc dirt bike or even scooters, those bikes are typically too tall, too fast, and too heavy for first-time riders. A 50cc offers the right balance of safety, fun, and skill-building.
Also Great for Smaller Adults (With Caution)
Technically, a small adult can ride a 50cc motorcycle for light commuting or short-distance fun. Just be aware that heavier riders will limit speed and may affect how the bike handles. If you’re an adult looking for something small and nimble for the street, you may be better off with a scooter or a dual-sport bike with a larger engine.
Start Small. Ride Smart. Go Far.
Now you know how fast a 50cc dirt bike can go, typically between 40 and 65 km/h, or around 25 to 40 mph. While they may not be the fastest dirt bikes out there, they’re exactly what new riders need: safe, simple, and confidence-building.
Wondering how 125cc compares to other engine sizes? Check out our full guide on how fast powersports vehicles go.
Visit your nearest RideNow Powersports location. We’ve got over 50 stores across the U.S., expert staff, and the best selection of beginner-friendly bikes from Honda, Yamaha, KTM, and more. Browse our 50cc inventory at RideNow.com and get your young rider geared up to ride smart from the very first start.