Here are the fastest stock ATV top speeds for comparison. They are the fastest 4 wheeler top speeds as reported by the people and/or organizations listed. If no organization or person is listed I included the name of the website who offered plausible recorded speeds with video evidence.
I do not recommend speeding even if only to find out what your ATV’s top speed is, that’s why we have the internet. Now onto the stock ATV top speed reports:
Fastest Stock ATV Top Speeds by Brand
In July 1988: A stock LT500 ATV, better known as Quadzilla, went 79-80MPH during testing by 3×4 Wheel Action magazine
In 2001: A stock Yamaha Raptor 660R went 74-75MPH during testing by Yamaha Motor Co. They later suggested that the Yamaha Banshee was capable of similar speeds.
In 2001: BRP announced that their year old stock DS650 ATV was capable of reaching a top speed of 75-77MPH
In 2004: Dirtwheels magazine reported that during testing they clocked a stock Yamaha YFZ 450r at a top speed of 75MPH
In 2008: Polaris joined the speed fray with their stock Outlaw 525S ATV at around 75MPH
In 2010: Arctic Cat brought their Behemoth 1000cc stock Thundercat ATV to a top stock speed of 79MPH which, considering it is a utility ATV and not a sport ATV, is pretty impressive.
In 2016: Yamaha’s YFZ 450 recorded a stock top speed of 75MPH at a Texas raceway.
A stock KFX 400 top speed approaches 69MPH according to several people who contacted me directly.
I was recently asked how fast a Kawasaki KFX 400 ATV could go and from memory I answered somewhere in the 65MPH range. ATV age, altitude, after-market parts, terrain type and general condition play an important role in determining top speed.
I asked on Twitter and searched a few of my favorite hot-spots to find that others have topped out at around the 68-70MPH range on their KFX 400’s. I don’t recommend trying it yourself on a used ATV, especially if local laws prohibit you from riding on roads, but I did find a video of what that might look like to reach top speed on a KFX 400, take a look.
If you own one, and have already found out first hand, I’d love to hear your results on twitter.
There have been other notably fast stock ATVs over the years and I’d like to track down the top speeds of some slower but not less popular ATV brands in the near future.
UTVs and Side by side vehicles are now common in the marketplace and due to having larger engines can go even faster than the speeds listed above, if conditions are favorable.
My opinion: Top speed isn’t as important as acceleration in an ATV because you’re likely to be riding in rough terrain. You will need to throttle up and down too often to reach top speed anyway. Still, it’s fun to have a baseline of your quad’s top stock speed before you upgrade it with performance parts. I hope the figures above helped.
How can I increase ATV top speed?
The top speed of an ATV is limited by the final gear ratio and wheel size. Horsepower and weight only determine how long it will take to reach top speed, the final gearing ratios absolutely set maximum possible speed on an ATV. You can only go as fast as the gear ratio will allow. A lighter ATV and more powerful engine will accelerate more quickly but at max RPM the gear ratio dictates top possible speed.
You can increase your quad’s acceleration rate by reducing weight and increasing horsepower. If you truly want to reach a higher top speed you have to install taller and steeper gears. Tires with a longer radius can also help you reach higher speeds, assuming the engine is capable of accelerating enough to make use of the extra size. A larger tire circumference increases top potential speed but it also lowers acceleration rates slightly.
I often see questions asking what is the top speed of a 125cc engine or a 90cc engine or a 450cc engine. Engine size doesn’t dictate top possible speed, it dictates the acceleration rate in getting to the max potential top speed that your current gear ratios will allow.
To get a good ATV top speed comparison start with a stock engine and increase tire size slightly. You will probably notice that it takes a bit longer to reach the same top speed you did with the smaller tires. After you change the gearing ratios it will become even more noticeable. Your ATV will NEED more power to reach the new limits but it’s not the horsepower that makes the higher top speed possible.
You’ll also notice that gains are not linear, they are exponential. The first increase in tire size may need a small amount of horsepower increase to maintain the same acceleration rate. A second increase in tire size, by the same amount, will need more of an increase than the first one did to maintain the same acceleration rate. An ATV dragster has gears so steep you would probably find them extremely unrewarding to ride with a stock engine. I hope that helps you understand a bit better why more horsepower does not equal a higher maximum top speed all by itself.
Fun Fact: The top speed on an electric battery powered ATV is not limited by the same constraints. Theoretically the tires can spin as fast as the amount of current the motor turning them is able to tolerate. With batteries big enough to sustain a high output for long enough an electric ATV has much higher potential, and the acceleration is equally much stronger. Speed limitations on a battery powered quad are battery size, electric motor capacity, friction, heck even wind resistance will come into play at some point. Future ATV speed records belong to electric quads, as soon as batteries become more affordable and easier to recharge.