Dirt Bikes

2024 Yamaha YZ125X Technical Information

Closer look at the YZ125X and some of its differences compared to the YZ125.

March 9, 2024

Having received significant updates in 2023, Yamaha’s YZ125X remains unchanged mechanically for 2024. Before testing bLU cRU’s 125cc two-stroke cross-country racer at Randy Hawkins’ private ranch in Union, South Carolina, we pointed our cameras at it to showcase a few highlights and technical differences compared to the YZ125 motocross model. Keep scrolling to learn more about the 2024 Yamaha YZ125X.

Visually, the 2024 Yamaha YZ125X looks almost the same as the 2023 model, with only a minor update to the graphics.James Lissimore

In 2023, Yamaha introduced a more powerful 125cc two-stroke engine with improved fueling via a Keihin PWK 38S carburetor.James Lissimore

The cylinder, cylinder head, and crankcases were new for 2023, and same goes for internal components such as the connecting rod, piston, and piston pin.James Lissimore

The YZ125X uses the same close-ratio six-speed gearbox as the YZ125.James Lissimore

The Keihin PWK 38S features a power jet circuit, throttle position sensor, and 3D-map-controlled CDI with precise ignition timing.James Lissimore

The reed block is a crucial part of two-stroke engine performance. Yamaha chose a highly regarded Moto Tassinari VForce4R reed cage known for maximizing throttle response and peak power.James Lissimore

This racebike is designed for GNCC, enduro, and other forms of off-road competition, so there’s no spark arrestor here.James Lissimore

Unlike a motocross bike, off-road riding and racing requires a fuel petcock with a reserve feature.James Lissimore

The YZ125X uses the same KYB Speed Sensitive System (SSS) 48mm coil-spring fork and KYB shock as the YZ125 with 4.2 Nm and 48 Nm spring rates, respectively. Internal valving, however, is tuned specifically for off-road racing.James Lissimore

In 2023, the YZ125X and YZ250X received new integrated body panels, a narrower fuel tank, slimmer radiator shrouds, and a flatter seat.James Lissimore

While the YZ125 motocrosser comes with a 19 x 1.85 rear rim and Bridgestone Battlecross X20 tires, the YZ125X features an 18 x 2.15-inch rear rim and Dunlop Geomax MX33 rubber. The 240mm rear disc also gets a guard.James Lissimore

In 2023, Yamaha updated the front brake to a more rigid caliper with larger pistons, and a redesigned 270mm front rotor.James Lissimore

An O-ring chain and one-tooth-larger rear sprocket are spec’d on the YZ125X for tight woods riding.James Lissimore

The YZ125X comes equipped with a very sturdy aluminum sidestand. For those who want to take it off, they can replace the footpeg mount with the motocross model’s.James Lissimore

The 2024 Yamaha YZ125X comes in Team Yamaha Blue, has a suggested retail price of $7,199, and is available now.James Lissimore

2024 Yamaha YZ125X Specs

MSRP:	$7,199
Engine:	Liquid-cooled, two-stroke single-cylinder
Displacement:	125cc
Bore x Stroke:	54.0 x 54.5mm
Compression Ratio:	7.8~10.2:1
Transmission/Final Drive:	6-speed/chain
Fuel System:	Keihin PWK 38S 38mm carburetor
Clutch:	Wet, multiplate; cable actuation
Frame:	Semi-double cradle aluminum
Front Suspension:	KYB Speed Sensitive System (SSS) 48mm coil-spring fork, compression and rebound damping adjustable; 11.8 in. travel
Rear Suspension:	KYB shock, spring preload, high/low-speed compression damping, and rebound damping adjustable; 12.4 in. travel
Front Brake:	Nissin 2-piston caliper, 270mm disc
Rear Brake:	Nissin 1-piston caliper, 240mm disc
Tires, Front/Rear:	Dunlop Geomax MX33; 80/100-21 / 110/100-18
Rake/Trail:	26.4°/4.4 in.
Wheelbase:	57.3 in.
Ground Clearance:	14.0 in.
Claimed Seat Height:	38.2 in.
Fuel Capacity:	1.8 gal.
Claimed Wet Weight:	212 lb.
Availability:	Now
Contact:	yamahamotorsports.com