Yamaha just released the 2020 YZ125X two-stroke. This is an off-road version of the YZ125 motocross bike, similar to the YZ250X. The bike is another sign of the commitment that Yamaha is showing to the two-stroke. It doesn’t represent any new technology, but it does show that the company still believes in the two-stroke as a platform and isn’t afraid to try something new. We got to spend a couple of days riding it in the deep south, at the home of Randy Hawkin’s Ampro Yamaha off-road racing team. It was a blast, and we came away wanting more of the little X.

The 2020 Yamaha YZ125X is the new off-road version of the YZ125 motocross two-stroke.

The YZ125X looks almost exactly like the 2020 YZ125 motocross bike, which, in turn looks like the 2015 YZ125. That was when the bike got its last makeover, and even that was mostly superficial. The underlying tooling and design has been around since 2005. All of the other Japanese manufacturers abandoned the 125 two-stroke in that period, but Yamaha didn’t see anything wrong with keeping the bike in the line for the two-stroke faithful. The bike has been a solid seller ever since. In 2016 Yamaha actually expanded its two-stroke offerings with the YZ250X, which was the first off-road two-stroke since the 1998 WR250. Now the 125 gets similar treatment. The outward changes that make the YZ125 into an X are the 18-inch rear wheel and the kickstand. Within the motor, there are some significant other changes. The combustion chamber is larger, (10.1cm3 vs. 8.4), the powervalve is reshaped and its governor has a stiffer spring to make the valve open later and more slowly. The ignition timing is also changed, with 5 degrees more advance at low-to-mid rpm levels. The X still uses the same KYB suspension components, but the valving is lighter for off-road use.

The power delivery and suspension of the YZ125X were retuned for off-road riding, but it’s still a YZ125 at its core..

Unlike the 250X, the gear ratios are the same as those of the MX bike. It remains a fairly close-ratio six-speed, but the final gearing is lower because of a 50-tooth rear sprocket. Another thing that is the same as the MX bike is the fuel-tank capacity (2.1 gallon). Yamaha could have gone a little crazy with a bigger tank, handguards and maybe even a headlight, but that would probably have been a deal-breaker for the whole project. The price had to be kept low. The 125X sells for $6699, which is $100 more than the MX bike. European manufacturers have recently been diving back into the 125 two-stroke category with their own off-road bikes. There’s a Beta 125RR for $7999, a TM EN125 for $8695, a Sherco SE125 Racing for $8399, a Husqvarna TE150 for $8899 and a KTM 150EXC for $8799. The latter three have electric start. The Yamaha’s price is a big part of the appeal.

Riding any 125 on the trail is a study in adrenalyn. You have to be excited and aggressive to keep it on the bubble. With the X, though, you can lay off the clutch for level sections of trail. It has more low-end than the stock Yamaha and the hit isn’t quite as hard. If the trail turns and goes uphill, you have to be ready with a downshift or some fancy clutch work. Then you have to be ready with a quick upshift, because the motor doesn’t rev nearly as high as a modern four-stroke. The 125X isn’t for sleepy trail rides. It’s for fast-paced riding and play racing. That’s fine with virtually everyone who rides it because the bike handles like magic. It makes you want to ride hard. We didn’t have a scale with us, but we know that the YZ125 weighs 201 pounds without fuel, and the X should only be heavier by the weight of a kickstand. Riding a bike that light makes you a superhero. You can get away with almost anything. 

In typical Yamaha fashion, the suspension is excellent. It is soft, though. The bike is set up for younger riders. This would probably be an excellent bike for kids transitioning out of the mini ranks in motocross. It’s also a great machine for older riders who don’t want to carry around a 450 on the trail. Most plus-40 off-road riders don’t know it, but they would be much happier on a 125.

The bike’s biggest limitation is in the racing world. It gives away a little too much outright horsepower compared to 250cc four-strokes and European 144cc two-strokes. Even though its handling is phenomenal, it would take a lot of work to make up for 10 horsepower or so just by diving into corners harder and braking later. The YZ125X’s true domain is the fun ride. That’s where it beats almost everything on wheels. Stay tuned for more on the 2020 YZ125X as we ride it back to back with the new YZ250FX four-stroke.

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