What We’ve Learned Racing A 2021 Kawasaki KX250X

Racing Team Green’s KX250X

Story by Trevor Hunter

Chance started it off for us and put us in the running in the early laps.

As stated in our Bike Test, Kawasaki’s KX250X is a purebred off-road racer. Very closely resembling the MX bike, the X model feels like you’re riding a motocross bike off-road, which isn’t necessarily a bad thing. Those who are a bit more aggressive will appreciate the characteristics. Handling-wise, the bump absorption, comfort, and performance the chassis boasts are very good. The bike is light feeling, nimble, and precise, but its stability doesn’t falter when you get off the motocross track. The suspension is stiffer in nature but could benefit from some stiffer springs for our Pro level and huskier vet testers. Motor-wise, it performs best when being ridden like a traditional 250F, which is revved out. On the top end, the bike moves and is one of the faster bikes in the class. It doesn’t have the torque or lugability that a Yamaha has, which can be detrimental in certain off-road conditions, but it also isn’t the worst in the class.

We raced this bike in four different races: a Glen Helen SRA Grand Prix, a Big6/NGPC in Taft, the 6 Hours of Glen Helen (check out our Race Report HERE), and a District 37 Sprint Enduro in the desert. All four races were quite different, but the bike transitioned well across them all. It definitely suited the Sprint Enduro best, where you’re on the bike for short periods of time and you really have to be aggressive and precise with the bike. At the 6 Hour, it impressed us with how it performed in the wide variety of terrain, from 70MPH+, square-edged straightaways to first gear tight singletrack canyons and rocks.

We’ve had a few testers ride and race this bike, from Pro level off-road racers to experienced Vet riders, and one common theme we’ve found with this bike is the high fun factor. Riding this bike, it puts a smile on your face. The developed chassis paired with a free-revving motor boasts aggression, which in turn leads to fun. It can wear you out trying to get the most out of it and riding it similar to a 125cc two-stroke, but most 250F’s are like that. So, in our time with the KX250X, what did we learn the bike needs while racing it?

A larger tank is desperately needed. It’s hard to have an off-road bike with a small gas tank. Whether you’re trying to race or you’re going trail riding, you’re pretty limited on how far you can go. Luckily, EFI four-strokes are pretty fuel-efficient, but the tank is just slightly too small. We attempted to race a Glen Helen GP, which was mostly fast, though a few tight and technical sections were included, and we weren’t able to go the distance on the stock tank. In a 60-minute race with a Pro level rider, we made it 55 of the 60 minutes before running out. We almost made it, but almost only counts in horseshoes and hand grenades. We borrow an IMS 2.8 gallon tank from the Precision Concepts crew and it is much needed. It didn’t affect the handling much, but it adds quite a bit of mileage to your ride/race. A good portion of off-road riders ultimately add a dry-break ready tank to their bikes anyways, so it’s not entirely a deal braker, but a lot of people do rely on using the stock, larger capacity tank for racing and trail riding.

Next up, we swapped the 51T Rear Sprocket for a smaller 50T Supersprox Sprocket like the MX bike has. Out West, everything is pretty fast so there is no need to have a 51T sprocket. We could even go with a 49T if the conditions are really fast, but the 50T works good all-around.

Finally, we were looking for a little better durability and performance out of our two contact points, the wheels, so we went with some different Dunlop Tires and some Nitromousse foam inserts. The MX33 isn’t necessarily our favorite front tire, so we opted for the more well-rounded MX53 front tire. It crosses over from Soft to Intermediate to Hard packed terrain quite well, with a consistent performance across all of the different conditions. Out back, we put on another AT81 rear, though it’s not our favorite tire, it works good. We had some durability issues with our AT81 tearing it open in two spots, but we were hitting some good sized and sharp rocks at a high rate of speed in the 6 Hours of Glen Helen which certainly lead to it splitting open. Still, it made it to the finish without an issue since we had Nitromousse’s installed.

A Dunlop MX53 was our front tire of choice as we prefer that over the AT81.

Even though those were the only modifications we made, we found some weak spots that can and should be addressed. The skidplate isn’t built for off-road at all, as it is pretty light and flimsy, and doesn’t offer much protection. TM Designworks, Acerbis, and others all make very good Skid Plates that will get the job done. Also, the Chain Guide and Slider wears quickly, but that isn’t new. Again, TM Designworks offers a very durable setup that will outlast the stock components tenfold. We also saw the chain stretch drastically throughout the 6 Hour, even though it only had 14 hours on it prior to the race start. Most off-road bikes come equipped with O-Ring Chains, but even this one stretched quicker and easier than a standard chain should. We also broke a couple of teeth off the countershaft sprocket, but that could’ve been due to the loose chain. In short, the drive system on the KX is a weak point, but those are all high wear items on any bike. Handguards don’t come stock, so we added some Polisport Hammer Handguards to protect our knuckles from roost and bushwacking.

Another wish, and this is a big one, is to have a 6th gear. KTM has a 6th gear in their 250 XC-F, but it is so tall, it is almost impossible to pull unless the conditions are right. Yamaha has a wide-ratio 6-speed transmission, but those aren’t everyone’s favorite due to large gaps between gears. However, the bike has a motor to pull it off. For the KX, we’d love to have an evenly spaced 6th gear to get better top speed in faster conditions and to be able to cruise at a higher rate of speed while trail riding. Lastly, the stock Kawi grips are tough. They are rock solid and tear your hands up. Installing your grip of choice is highly recommended.

Check out some of the abuse that the 6 Hours of Glen Helen did to our KX:

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