My very first dirt bike was a Yamaha YZ250. My second dirt bike was the one we are covering here in this article — a Yamaha YZ250F. Naturally, one of the things I wanted to know is what is the YZ250F top speed?
In this article, we will answer what the YZ250F top speed is and what things impact it.
YZ250F Top Speed
Yamaha, known today for its motorcycles and musical instruments, released its first dirt bike in the mid-1950s.
It hasn’t always been this way, but today, many people are thinking of Yamaha as having the fastest machines. At least in the motocross racing world and with Yamaha’s big bikes, like the YZ250F and YZ450F.
Star Racing Yamaha is building out one of the biggest professional motocross and supercross teams, and many riders are excited to go there because of how good the team and bikes are.
Eli Tomac just switched to Yamaha this past year and swept nearly every major, professional title there was.
What does this mean for the YZ250F top speed?
The YZ250F top speed is about 65-75 mph. The fastest stock motocross 250 in its class.
This is about 10-15 mph faster than the YZ 125 top speed. It’s also about 3-5 mph faster than the KX250F top speed. A CRF250R’s top speed and the KTM 250 aren’t far behind the YZ250F either.
Why did I pick these two bikes to compare the YZ250F?
First, the YZ125 was picked because 125cc dirt bikes are a natural progression for kids to move on from when they’re going to start riding 250s. There isn’t really much for race bikes in-between. Kids will frequently jump from a 125 to a 250.
For the KX250F, this was chosen because Yamaha and Kawasaki have two of the most popular 250 motocross bikes on the market and that leads to people always being curious which one is faster.
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What changes the top speed of YZ250F?
It can be tough at times to calculate the true top speed of a dirt bike because there are quite a few different items that can impact it. Let’s take a look at them.
Modifications
This might be obvious to some, but engine work and aftermarket parts are going to impact the YZ250F top speed. Arguably, most of anything.
If your YZ250F has engine work and a pipe, that’s not really comparable to the top speed of a stock YZ250F.
A Star Racing Factory Yamaha team’s YZ250F is going to be significantly faster than the stock YZ250F I bought off the dealership floor.
The top speed of YZ250F that hasn’t had any work done to it will be significantly lower than the top speed of YZ250F that has undergone mods.
The more work you do to the bike, the greater the difference in speeds will be.
There are other factors at play here too – such as gearing, riding conditions, and more.
Gearing
The second most important factor in determining the YZ250F top speed is its gearing. Gearing refers to the size (and ratio) of the front and rear sprockets.
For reference, the stock gearing for this bike is a 13-tooth front sprocket and a 50-tooth rear sprocket (depending on the year of your bike).
Riders normally pick different gearing depending on the situation they’re riding. If the rider is racing supercross, they would typically want more acceleration (referred to as more bottom end). To achieve this, they’d use either a smaller front sprocket or a larger rear one. This is known as having a low gear ratio.
If the rider is racing motocross, they may want more top speed (known as top end). To do this, the rider would use a larger front sprocket or a smaller rear sprocket; in other words, they would be changing to a higher gear ratio.
Riding in the woods can require an entirely different gearing combination than that of supercross or motocross.
This might not sound like much to some people, but it has a large impact on the top speed of YZ250F (or any dirt bike, for that matter). Depending on the gear changes made, it can increase or decrease the YZ250F top speed by more than 5-10 mph.
A YZ250F with an 8-tooth front sprocket will have a different top speed than one with the stock 14-tooth front sprocket (I made the difference wide to make a point — no one is running an 8-tooth front sprocket on their YZ250F….).
Additionally, a change to the front sprocket has a great effect on the YZ250F top speed and bottom end than changing the rear sprocket. Going up or down one tooth on the front sprocket is not equal to one tooth on the rear sprocket.
Rather, changing the front sprocket by one tooth is equivalent to 3-4 teeth in the rear.
Rider
The top speed of YZ250F is going to be slower if the rider weighs more because it takes more work from the bike, while the bike and engine maintain the same ability/capacity. The heavier the rider, generally the lower the YZ250F top speed is going to be.
In addition, an experienced rider can make the YZ250F go faster than a beginner who is just learning. A rider who knows how to quickly and smoothly shift gears can hit a higher top speed than someone who is just learning how to use a clutch.
Haiden Deegan or Christian Craig on a YZ250F will be able to go faster than a young kid who got one for their first dirt bike.
Conditions of Riding
The YZ250F top speed can also be impacted by riding conditions, including both location and surface.
For example, a dirt bike’s power output is generally higher closer to sea level than at high altitudes. So if you’re planning to ride your YZ250F in the mountains, it will likely have a lower top speed than if you were riding at sea level.
Or, even if you’re not in the mountains necessarily, but you’re just riding in Colorado, you’re much higher above sea level than the coasts of the US. That will cause your YZ250F top speed to be lower.
Smaller-size bikes (bikes with small cc engines) are more impacted by elevation changes than larger bikes, too. For example, a YZ250F is more impacted by the elevation changes than a YZ450F. This is discussed every year when Lucas Oil Pro Motocross heads out to Thunder Valley in Colorado.
Are you riding in the woods, on a motocross track, or on a paved road? If it’s in the woods, your top speed might be limited. If you’re racing motocross, you can only go so fast while remaining safe and within bounds (and, don’t forget, sometimes slow is fast).
Apart from the elevation and location, another factor that affects the YZ250F top speed is the surface on which it is being ridden. The top speed of YZ250F ridden on flat pavement will be different than if it were driven on a tight, sandy motocross course; even the type of tires can make a difference.
A Few Other Factors that Can Impact the YZ250F top speed
Your YZ250F top speed can also be impacted by a few more things, including the condition of your bike, the weather, and how you’re recording the data.
A bike that is regularly maintained will run faster and more efficiently than one that isn’t. For example, a YZ250F that has had consistent maintenance done to it will be able to reach a higher top speed than one not taken care of properly.
A bike that has 150 hours on its top end is going to perform differently than one with 5 hours on it.
The weather and temperature can both affect your YZ250F top speed. If it rains, the pavement will be wet and your top speed will probably be lower than normal.
If you want to get an accurate reading of the top speed of YZ250F, use an onboard GPS device rather than relying on someone pointing a speed gauge at you as you zoom past. This doesn’t mean the bike will actually go any faster or slower, it just changes what you end up seeing on paper.
Waving the White Flag on the top speed of YZ250F
As we pass by the white flag of this article and enter into the last lap, we want to summarize what we’ve covered so far.
Ultimately, most people want to know their bike’s rough top speed. Yes, mods and other items impact a YZ250F top speed potential, but at the end of the day, people just want to have an idea of how fast their bike is.
With that in mind, a YZ250F top speed is about 65-75 mph.
Frequently Asked Questions About the YZ250F Top Speed
How fast a Yamaha 250 can go depends on whether you’re referring to a YZ250F or a YZ250. The F on the end is a small difference in the name, but it’s a huge difference in the bike. The YZ250 is upwards of 50hp and can do 75-80 mph, while a YZ250F can only do about 65-75 mph.
A YZ250 is a faster dirt bike than a YZ250F, despite both bikes having the same size engine (displacement). This is because the YZ250 is a 2-stroke, while the YZ250F is a 4-stroke.
As of this writing, the Yamaha YZ250F holds the crown for the fastest 4-stroke 250.
The power of a YZ250F can be quantified by its horsepower, which is about 38.9 hp.
A 250F dirt bike can go about 65-75 mph.
The CRF250R and YZ250F are very close in speed, but the nod goes slightly to the Yamaha YZ250F for which bike is faster.
Yes, the Yamaha YZ250F is a motocross race bike. It doesn’t have to only be raced, but it is designed to be a race bike.
Yes, the YZ250F is fuel injected these days.
Yes, the Yamaha YZ250F has a liquid-cooled engine.
