TEST UPDATE: 2023 YAMAHA YZ125 TWO-STROKE

On Apr 26, 2023 Last updated Apr 26, 2023

HOW IS THE 2023 YAMAHA YZ125 ENGINE? The Yamaha YZ125 engine is really fun to ride and great for learning how to feather the clutch and carry momentum in the turns, but it’s not great for keeping up with Austrian-built 125s. The YZ125 gives up power on the bottom and the top end when compared to its Austrian competition. Before it was updated in 2022, the YZ125 was better than the KTM 125 at the crack of the throttle, making it a great choice for beginners to learn how to ride a 125. Unfortunately, Yamaha stole power from the YZ125’s bottom-end snap to search for more mid- and top-end power.

HOW FAST IS THE ’23 YZ125 ENGINE ON THE DYNO? The dyno visually displays on a graph what you see and feel on the track. The YZ125 starts slower than the Austrian 125s and catches up to them briefly, at 7500 rpm, only to be left behind at 8000 rpm when the YZ takes a breather and the red, orange and white bikes take off. From 8000 rpm on, the YZ125 doesn’t hold a candle to the KTM, Husky, or GasGas 125s. The Yamaha does rev slightly farther than the competition, to 11,700 rpm, but it peaks at 35.64 horsepower, a horse and a half off KTM and Husky, and almost 3 horses off the GasGas MC125.

COULD THE ’23 ENGINE BE BETTER? The dyno chart tells the tale of the 125 class. Because all 125 two-strokes are relatively lightweight and low on horsepower, they all handle pretty well. This makes horsepower that much more important. The YZ125 is ultra-fun to race against other YZ125s, but it’s not as much fun to race against the high-horsepower Austrian 125s. The YZ125 engine could be better if it had more top-end power and/or more bottom-end power.

HOW GOOD ARE THE YZ125 FORKS? Since 2006 we’ve been praising Yamaha and Kayaba for their speed-sensitive damping (SSS) forks. These bump stoppers have been the largest factors in helping the YZ125 continue to be nominated as “the most fun bike to ride” for almost two decades. Yes, Yamaha went for a little more hold-up on the forks last year when they introduced their updated YZ125, but their forks are still on the soft side when compared to the air-forks on the KTM 125SX, which can be made stiffer with a hand pump at the track.

WHAT ABOUT THE REAR SUSPENSION? The KYB shock is good also. Like the forks, it’s on the soft side for heavier and faster riders, but it still offers a predictable action that any of our test riders can make work.

HOW DOES IT HANDLE? The YZ125 handles like a dream. It’s lightweight, the aluminum frame is perfect and the suspension is plush. Plus, the YZ125 engine makes good power in the midrange, which helps its handling. In general, 125 two-strokes are great for riders advancing from 85s and Superminis to the big bike classes, but the YZ125 is especially good for young riders because of its plush suspension.

WHAT DID WE HATE? Yamaha came out with what was touted to be an all-new engine in 2022, but the new YZ power producer didn’t live up to its hype. KTM’s 125 advancements since 2006 have built up a hefty power gap that Yamaha didn’t quite close in ’22. We wish it had more power.

WHAT DID WE LIKE? (1) First, we appreciate that Yamaha is still producing (and updating) YZ two-strokes. The other Japanese manufacturers gave up on the two-stroke market, and we applaud the blue crew for staying true to the core riders of our sport. (2) The YZ125’s chassis is very comfortable, and all of our testers drool over the KYB SSS forks.

WHAT DO WE REALLY THINK? The 2023 Yamaha YZ125 is the last Japanese 125 two-stroke standing. Riders choose the Yamaha over the orange, white, and red Austrian bikes because they either can’t stand to own a KTM (no matter the color), they can’t stand air forks or they can’t stand the chromoly steel frame. It may be true that if you normally ride a KX250, CRF250, RM-Z250 or YZ250F, you’ll feel more at home on the YZ125 because of its coil-spring SSS forks and plug-and-play aluminum frame. We don’t blame these riders too much. The YZ125 is a fun bike, and the aftermarket has an abundance of upgrades for it; however, if you’re a serious racer, it’ll take a lot of work to get your YZ125 to run like the GasGas MC125, which was Motocross Action’s 125 Shootout” winner for 2023.