Cycle News Staff | February 28, 2020
2020 Yamaha YZ125X Review
The Yamaha YZ125X might be a “small-bore,” but it packs a big punch of two-stroke fun.
Yamaha expanded its off-road two-stroke line with the YZ125X.
Once again, we applaud Yamaha for not ignoring the two-stroke. Yamaha has never really given up on the premixers despite being the manufacturer having the distinction of starting the beginning of the end of the two-stroke off-road motorcycle when the YZ400F was released in the late 1990s. But you can’t blame Yamaha, though. If they hadn’t done it, someone else would have. While all of the other Japanese manufacturers eventually gave up on the two-stroke, Yamaha stayed true to the blue smokers, keeping the YZ250 and YZ125 motocrossers in its YZ lineup while keeping yearly updates to a minimum (if at all).
Despite the four-stroke revolution, two-strokes remained popular in the off-road, or enduro, world because of their light weight, snappy power and simplicity. After all, off-roaders are simple people, right? And us off-roaders are proud of that. Yamaha noticed how so many racers were switching back over to two-strokes in the woods and introduced the YZ250X, an off-road version of the YZ250, in 2016. And Yamaha expanded its camless offerings in 2020 with an all-new two-stroke model, the YZ125X.
Yes, the model might be new, but not the technology. The YZ125X is closely related to its YZ125 cousin, which has been hanging around since 2005—the last time the YZ125 got a significant makeover. The YZ125 did get some attention in 2015 but mostly in the styling department. But the suspension was also retuned. The 2020 YZ125X is a YZ125 in off-road trim, featuring softer suspension and a motor tuned for more bottom-end torque, two best friends of the off-roader.
The YZ125X could easily pass as its YZ125 cousin.
Off-roaders can see the difference, but to most, the YZ125X could easily pass as its YZ125 cousin. Visually, the YZ125X and YZ125 are nearly identical. The kickstand, however, is a dead giveaway that the X is not a motocrosser, and hard-core enduro riders will quickly notice the 18-inch rear wheel and the X’s Dunlop AT81 tires versus the YZ’s Dunlop MX52s. Otherwise, you can’t tell the two apart.
Internally, the X has been tuned for the trail. Now, this doesn’t mean that Yamaha made it slower or less exciting; instead, they just altered how and when the power comes on to make it more trail-friendly. Compared to the YZ125, the X has a slightly larger combustion chamber, the power-valve is reshaped, and its governor uses a stiffer spring, resulting in the valve opening later and slower. Ignition timing has changed, too. Everything else about the X is the same as the motocrosser, right down to the suspension, which has been tuned a little softer for the trail and for younger riders, which Yamaha feels will be attracted to this motorcycle.
The X also uses the same transmission and internal ratios as the motocross YZ, but the X’s final gearing is slightly lower with its 50-tooth sprocket.
The YZ125X is proof positive that 125cc two-strokes do make fun, and even competitive, off-road bikes.
No, the YZ125X doesn’t have an electric start, but with this bike, who cares? It’s an easy motorcycle start even if you do have to kick it. We admit that we’re lazy, but not that lazy. And one of the most appealing things about 125cc two-strokes is their light weight, so why mess with that by adding a starter motor and battery when it doesn’t really need them? The X barely weighs over 200 pounds as it is! We’d just as soon keep it that way.
On the trail, this bike absolutely rips. It might be a 125, but it is a very fast motorcycle, even in the woods. It’s been a while since we rode a 125 in the woods, and we were surprised by how few times we wished for more top-end speed before the next bend in the trail came up. So much fun!
Oftentimes when it comes to 125s in the woods, the price you pay for having such a fast motorcycle is the lack of slow-speed manageability. In other words, no bottom-end or very little torque. This really isn’t the case with the YZ125X. Yamaha did an excellent job giving the X far better chugability than the YZ125 and making the power very useable and manageable in tight and technical situations—for a 125, of course. Yamaha found the right balance between high-end revs and low-rpm controllability.
That’s a YZ125 motor been tuned, but by all means, not “de-tuned” for improved bottom end and torque. The X is still plenty fast!
Sometimes you do, however, have to plan ahead when exiting a tight turn that is followed by a steep hill or a stretch of soft sand; you need to think about keeping up your momentum, tapping down on the shift lever once or twice before the turn and slipping the clutch as you aggressively get on the throttle coming out of the corner. Oh yeah, and don’t forget about having to change gears quickly and often right in the meat of the powerband as you accelerate out of the turn. Done correctly, and the X can hang with larger-capacity bikes, no problem. Done wrong, and you will pay the price big-time and get dropped bike the big bikes. The X forces you to be a better rider when it comes to turns and thinking ahead. Otherwise, the X is an adrenaline rush, for sure.
The suspension and handling combo is pure magic. The X is so light and maneuverable it gives you tons of confidence to be super aggressive, and it makes you feel like a superhero. And the suspension soaks up everything in its path nicely. Riders over 170 or so pounds, however, will probably want to stiffen things up a bit, but for lighter riders, which this bike is really meant for, the suspension feels just about right, not too soft, not too stiff.
An 18-inch rear wheel is fitted to the back. Tires are Dunlop Geomax AT81s.
We love the compliance of the X’s KYB Speed-Sensitive System fork (which is fully adjustable) and the way it reacts to the smaller hits (such as small roots and sharp-edged rocks) at speed. The KYB single shock in the back has no problems keeping up.
Everything about the YZ125X feels light and effortless. Clutch pull has almost zero resistance yet still has a good feel, changing gears requires just a slight nudge from your left foot, the front brake is a one-finger operation, and getting the bike to change lines while zigzagging around a series of trees is an absolute breeze.
However, all this happens quite quickly on the X, and all that activity can wear on you bit; in other words, you can’t get lazy on the X and let the motor do all the work when you get tired. Riding the X fast, which is how it likes to be ridden, requires constant attention and a fair amount of concentration, work and energy. But there is no better motorcycle than a good 125cc two-stroke, like the Yamaha, to learn how to ride fast in the woods. The quickest way to the Pro class is spending a season or two racing a 125, the sooner in your career, the better. Yeah, so you might sacrifice a few trophies here and there, but you’ll make them up, and then some, later on.
The X uses the same fuel tank as the YZ125 but gets a fuel petcock with reserve.
The YZ125X has a lot of company in its class, but none of them are from its home country of Japan. KTM has the 150 EXC ($8799), Husqvarna has the TE 150 ($8899) and Sherco has its SE 125 Racing ($8399), TM has its EN125 ($8695) and Beta its 125RR ($7999). But look at the price difference. At $6699, the YZ125X suddenly looks like a steal. And, when needed, you have 15-plus years’ worth of parts and accessories for the X that are most likely already sitting there in the parts bin at your local Yamaha shop, which is probably right around the corner from your house.
It might be a 125cc two-stroke, but the X hooks up well in the mud. And you gotta love the X’s lightweight.
As a racebike, the YZ125X, we have to admit, is giving a lot up to the bigger-displacement bikes like 250Fs and the larger 150s from KTM and Husqvarna—there is no getting away from that. So if your goal is getting on the podium at your next GNCC or enduro against the bigger bikes, you’ve got your work cut out for you, but it the right hands, it is doable. But if you’re more interested in improving your trail-riding technique, or just plain having fun and mixing it up with the other racers around you, then you will always win on the YZ125X.
Yes, just pin it and have fun, and you won’t be disappointed with the YZ125X. CN
2020 Yamaha YZ125X Specifications
| MSRP: |
$6699 |
| Engine Type: |
Liquid-cooled, reed-valve-inducted, 2-stroke, single |
| Displacement: |
125cc |
| Bore x Stroke: |
54.0 x 54.5mm |
| Compression Ratio: |
7.4-8.8:1 |
| Fuel Delivery: |
Mikuni TMX 38 carburetor |
| Ignition: |
CDI |
| Transmission: |
6-Speed |
| Clutch: |
Wet, multidisc |
| Final Drive: |
O-ring chain |
| Frame: |
Aluminum, w/aluminum subframe |
| Handlebars: |
Tapered aluminum (adjustable) |
| Front Suspension: |
KYB Speed-Sensitive System (SSS) inverted fork, fully adj. |
| Rear Suspension: |
KYB single shock, fully adj. |
| Front Wheel Travel: |
11.8 in. |
| Rear Wheel Travel: |
12.4 in. |
| Front Brake: |
Single 270mm disc |
| Rear Brake: |
Single 245mm disc |
| Front Tire: |
80/100-21 in. Dunlop AT81F |
| Rear Tire: |
110/90-18 in. Dunlop AT81 |
| Rake: |
26.8° |
| Trail: |
4.6 in. |
| Wheelbase: |
57.3 in. |
| Seat Height: |
37.6 in. |
| Ground Clearance: |
13.8 in. |
| Fuel Capacity: |
2.1 gal. |
| Weight (wet, claimed): |
209 lbs. |
2020 Yamaha YZ125X Review
