For 2023, the YZ125X is all new from the ground up with a completely redesigned engine, improved fueling system, and new ergonomics to add a thrilling level of performance to this trail blazer!

The peak horsepower of the 2022 YZ125 is 34.44-horsepower compared to the 2021 YZ125's 33.38-horsepower on the same dyno on the same day.

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.

1974 The Yamaha YZ125 is a motocross racing motorcycle with a two-stroke 124.9 cc (7.62 cu in) displacement single-cylinder engine made by Yamaha since 1974. It is available to the public.

Specs

• Manufacturer. Yamaha. 2024. YZ125X. YZ125XR.
• Length. 84.8 in. 50.8 in. 32.5 in. Wet - 212 lb.
• Engine. 2-stroke; reed-valve inducted. 125 cc. 2.1 x 2.1 in. ( 54 x 54.5 mm)
• Front Suspension. KYB® Speed-Sensitive System inverted fork; fully adjustable. Travel - 11.8 in. KYB® single shock; fully adjustable. Travel - 12.4 in.

2024 Yamaha YZ125X This includes a narrower fuel tank and radiator shrouds, and more rounded seat. Rider triangle is said to be better as well with more legroom between the seat and footpegs, plus a revised handlebar position.

POWERFUL TWO-STROKE YZ125 ENGINE: Yamaha's advanced, liquid-cooled 125cc two-stroke engine provides impressive acceleration, thrilling mid- to high-rpm power, along with supreme usability.

ENGINE

The YZ125X isn't the best 125cc two-stroke off-road racer or the best 125cc two-stroke motocross bike. It is a compromise bike, but it might be the best all-around 125 two-stroke for a guy who wants to ride off-road trails this weekend and a motocross track next weekend.

Power is impressive! Chassis componentry is similarly updated with new suspension refinements for the YZ125, improving an already great ride that is forgiving for riders up to about 175 pounds, max. I'm pushing 180 these days, and I was at the max of that poor rear shock spring most of my test day.

The YZ125 represents an important evolution in Yamaha's two-stroke lineage. Yamaha engineers put considerable thought into developing a motorcycle that would be both dominant on the racetrack and user-friendly for developing riders looking to bridge the gap between recreation riding and competitive motocross.

Updates for 2022 Yamaha's YZ125 gets a brand-new engine that delivers better midrange to top-end power. Improved fueling is provided by a new Keihin PWK38S carburetor in place of the 2021 model's Mikuni, while a Moto Tassinari VForce4R reed valve system is now standard.

RACE-READY FEATURES: Complete with an aluminum handlebar, two-position adjustable handlebar clamp, wide footpegs, gripper seat, adjustable clutch lever with works-style cable adjuster and lightweight rear sprocket design, the YZ125 is competition-ready straight out of the crate.