Motorcycle specifications YamahaYZ 125 2025 Crampons and sensations

Yamaha is one of the last manufacturers to develop two-stroke cross-country machines. Since 2022, the YZ 125 has featured a completely redesigned, more powerful engine, an improved chassis and slimmer, more radical bodywork. This is the most competitive YZ 125 ever!

With significantly more power, greater ease of use, optimized handling, more powerful braking and improved ergonomics, it's becoming a top choice for riders who want top equipment to build confidence, gain experience and take their performance to the next level.

125 cm3 engine: optimized performance and improved handling

Yamaha engineers have created the most powerful engine ever fitted to a production YZ 125. In their quest for performance, the development team designed a 125 cm3 two-stroke block that develops significantly more power at medium and high rpm.

Virtually all the major components of the 2022 engine are new. Its complete redesign gives the Y Z125 a real advantage as soon as the grid drops. The increased power, combined with greater ease of use and improved over-rev management, means that drivers can take full advantage of the power gain in all sectors of the track.

new cylinder head, cylinder and piston design

The machine's cylinder head, cylinder and piston have been completely redesigned to deliver enhanced performance and optimized power. These major changes affect the combustion chamber, exhaust and cylinder, and contribute to improved combustion efficiency.

new YPVS system

To complement the cylinder head and cylinder changes, a new YPVS (Yamaha Power Valve System) has been developed. The maximum lift of the new exhaust valve has been modified, and the timing of its opening and closing has also been refined to improve engine performance and handling.

new Keihin carburetor and V-Force valves

One of the main features of the new engine is the use of a 38.1 mm Keihin PWK carburetor equipped with a solenoid-controlled Power Jet that provides an instant boost when needed. The new carburetor features a TPS (Throttle Position Sensor), which combined with a CDI controlled by 3D mapping, ensures optimized ignition timing. V-Force valves, new exhaust manifold design, new intake and new carburetor give the YZ125 rider sharper acceleration from the start, and more explosive power out of corners.

longer connecting rod and heavier crankshaft

Other internal modifications contribute to the increased power of the new engine, including a longer connecting rod and a slightly heavier crankshaft. The result is greater inertia, optimizing engine behavior and crankshaft balance to meet the demands of this extra power.

high-efficiency air intake system

One of the main features of the YZ 125 is its completely redesigned air intake system. By modifying the rear of the frame and the two side covers, and reshaping the base of the seat, Yamaha engineers have reduced resistance to incoming air by 15% and succeeded in significantly increasing overall intake efficiency. This not only significantly improves mid- and high-rpm pulling power and over-rev character, but also refines low- and mid-rpm throttle response for smoother operation.

shorter exhaust manifold and silencer

Since 2022, the dimensions and shape of the exhaust have been transformed to match other engine modifications, with the sole aim of optimizing power and comfort. The diameter of the manifold is slightly reduced at its widest point, and the silencer is 50 mm shorter.

reinforced, smoother transmission

The YZ 125's 6-speed transmission has been strengthened in 2022 to cope with the increase in maximum power. The secondary reduction ratio has been slightly increased thanks to the use of a 13/49 front/rear sprocket set - previously 13/48 - and to improve driveability, 5th and 6th gears have been slightly modified.

A new gearshift shaft and redesigned return spring provide smoother shifting; and to handle the increased power of this engine, the Yam features improved clutch springs.

more assertive, compact styling

The YZ 125 benefits from a slimmer fuel tank, a new seat and a new patterned design, giving it a radical, modern and athletic look, in harmony with the formidable performance of its engine - while giving the rider even greater chassis control.

flatter seat

To optimize riding, free up movement and facilitate body weight transfer, the upper surface of the saddle has been flattened by lowering the front by 6 mm and raising the rear by 5 mm, while the new fuel tank is perfectly integrated into the front of the saddle. For ease of maintenance, a new single-bolt saddle clamp has been adopted.

narrower tank and radiators

The Yam YZ 125 is one of the lightest and most agile motocross bikes in its class. The current version is even slimmer, thanks to a new fuel tank and narrower radiators, making it the most compact YZ 125 in its history. The width between the rider's knees has been reduced by almost 36 mm to offer a real sense of slimness and agility, and improve rider ergonomics and mobility.

design of mudguards and side covers

To accommodate the new high-efficiency air intake system, the side covers, rear mudguard and underside of the new seat have been redesigned to facilitate the flow of air through the airbox. The shape of the front mudguard has also been revised to give a more aerodynamic and dynamic appearance.

new rear frame design

The YZ 125 is equipped with a high-performance aluminum semi-double-cradle frame, featuring unprecedented technical features and lightness. Since 2022, the rear of the removable frame has incorporated a new mounting point to accommodate a shorter silencer, while a new, raised crossmember improves intake efficiency by making it easier for incoming air to pass through. This new crossmember also accommodates the new single-bolt seat mounting point for easy maintenance.

revised suspension settings

The YZ 125's KYB front and rear suspensions are considered benchmarks in their class. They feature dampers for excellent mid-speed damping. Since 2022, the fork and rear shock have revised damping characteristics to improve chassis performance at low speeds.

more powerful front brake and lighter rear brake

For greater braking power and steering precision, this model features a new, stiffer two-piston front caliper and a redesigned 270 mm-diameter disc. Featuring 25.4 mm-diameter pistons and new pads that increase the contact area with the disc by 30%, this new, more powerful system enables riders to reduce their lap times by braking harder and therefore later.

new-generation colors and finishes

The YZ125 adopts a new two-tone Icon Blue finish, combining Yamaha's famous Icon Blue with a dark matte blue. The trim and new integrated graphics accentuate the dynamic, athletic look of this new-generation 125cc bike. By offering them a more competitive and attractive machine, Yamaha further confirms its commitment to young competitors.

yZ 125 50th Anniversary

In addition to the blue YZ 125, Yamaha is offering the "50th Anniversary" model with white trim, purple seat, retro purple/pink motifs and black rims in tribute to 50 years of YZ motocross bike production. The technical specifications of the 50th edition are identical.

yZ 125 highlights:

- a faster, sleeker model since 2022
- all-new, more powerful 125 cm3 engine
-greater mid- and high-rpm power , and improved rideability
- increased maximum power
- new Keihin carburetor with TPS and Power Jet
-redesigned YPVS system
-redesigned exhaust and shorter muffler
- new high-performance air intake
-stronger 6-speed transmission , revised ratios and improved clutch
-improved gear shifting
-lightweight aluminum frame
-redesigned rear frame
- new, slimmer trim - 36 mm narrower between the knees
- newly designed mudguards and side covers
-improved ergonomics with new fuel tank and flatter saddle
-more powerful braking system
-best-in-class KYB suspension with improved low-speed efficiency
- new two-tone Icon Blue color scheme with integrated graphics
- also available in Monster Black factory colors

Info and pictures: Yamaha France