Yamaha’s 2023 YZ125x & YZ250x Break Cover

When it comes to new Yamaha models for 2023, there’s no doubt the recently revealed 2023 YZ450F MX machine stole the show; a new-generation bike rebuilt from the ground up. And while that meant Yamaha’s 2023 enduro models flew under the radar a bit this year, it’s not because they haven’t copped notable upgrades. Admittedly, after the WR450F and WR250F came in for major overhauls in 2021 and 2022, respectively, it came as no surprise that those flagship enduro models remain unchanged for 2023. But what did a lot of people off guard was just how big an upgrade Yamaha’s two-stroke cross-country models copped – the YZ125X and, to a lesser extent, the YZ250X.

Essentially, the 2023 YZ125X is the beneficiary of the sweeping mods to the engine, ergos and brakes that were introduced to the YZ125 last year – the first all-new 125cc two-stroke MXer from Yamaha in 15 long years! Similarly, the 2023 YZ250X is now based on the 2022 YZ250 MXer, while both two- and four-stroke cross-country bikes (the YZ125X, YZ250X, YZ250FX and YZ450FX) all get new headlights.

Here is Yamaha PR, which delves deeper into the mods their 2023 two-stroke cross-country models come with…

2023 YAMAHA YZ125X…

The all-new 2023 YZ125X is ready to rip with a powerful, completely redesigned 125cc two-stroke engine, revised suspension damping, new lightweight braking system, improved ergos and a sharp new look. The ultimate step-up to full-size off-road performance.

ENGINE

Nearly every functional part of the engine is new – from the cylinder body, cylinder head, piston, piston pin, connecting rod, crankcase and expansion chamber, to a revised cylinder port shape and updated cylinder port timing. It’s a change that is immediately apparent at the first crack of the throttle and throughout the entire rpm range.

The YZ125X runs a revised compression ratio, revised YPVS timing and a model-specific digital CDI unit compared to its motocross sibling – all focused on creating a broad, usable power delivery specifically suited to cross-country and enduro-style competition. A revised close-ratio six-speed transmission has wider transmission gear tooth width and new, optimised gear ratios for maximum performance.

New high-precision Hitachi Astemo® Keihin PWK38S carburettor features a power jet, throttle position sensor and 3D-map-controlled CDI unit for precise ignition timing. The result is clean, crisp throttle response, superior rideability and excellent over-rev character.

BRAKES

An updated high-performance braking system features larger front pistons, a more rigid calliper and a redesigned 270mm front rotor with a 30% increase in pad contact area, all combining to provide exceptional braking power and feel. The redesigned rear rotor maintains the same braking power while dropping outer diameter from 245mm to 240mm, reducing unsprung weight with no compromise on performance.

ROLLING CHASSIS

A race-proven, highly developed aluminium semi-double cradle frame is engineered to provide the perfect balance of rigidity and flex for competition-ready handling character and composure. Removable aluminium rear subframe is constructed of square-section tubing for reduced weight.

The all-new YZ125X also features advanced KYB suspension, gripper seat and narrow fuel tank combined with a tapered aluminium handlebar and adjustable mounts, slick blue Excel rims and newly sized high-performance Dunlop Geomax MX33 tyres for improved cornering traction, stability and feel.

Other features include an 18-inch rear wheel, larger rear sprocket, sidestand, sealed O-ring chain, new headlight, reserve fuel petcock, and newly adopted scraper between the fork’s dust and oil seal, all adding up to exceptional off-road performance.

2023 YAMAHA YZ250X…

Based on the legendary 249cc YZ liquid-cooled reed-valve-inducted two-stroke engine, the YZ250X runs a revised compression ratio, exhaust port timing, Yamaha Power-Valve System timing and a model-specific CDI unit.

ERGOS

To increase rider confidence in challenging cross-country conditions, new smoothly integrated body panels, more narrow fuel tank design, slimmer shroud width and flatter seat all combine to enable greater freedom of movement forward and back, allowing the rider to easily shift body weight for better control.

BRAKES

[As per the 2023 YZ125X’s brake mods – see above].

ENGINE

To improve clutch durability without compromising smooth operation, six inner pressure plates adopt a new friction material with excellent heat resistance characteristics ideal for extended cross-country competition.

ROLLING CHASSIS

Further improving the YZ250X’s already renowned suspension performance, new front fork internals and revised suspension settings further improve bump absorption, cornering performance and comfort to better withstand the gruelling demands of off-road and enduro-style racing.

The YZ250X is focused on off-road competition and receives the same features as 125X such as 18-inch rear wheel, wide-ratio gearing (five speed, in this case), standard sidestand, sealed O-ring chain, reserve fuel petcock, new headlight and newly adopted scraper between the fork’s dust and oil seal, all adding up to exciting performance.