Key performance
Technical specifications
Engine
- Displacement
- 125 cc
- Power
- 40.0 ch (29.4 kW)
- Engine type
- Single cylinder, two-stroke
- Cooling
- Liquid
- Compression ratio
- 10.7:1
- Bore × stroke
- 54.0 x 54.5 mm (2.1 x 2.1 inches)
- Fuel system
- Carburettor. Mikuni TMX 38
- Lubrication
- Premix
- Ignition
- CDI
- Starter
- Kick
Chassis
- Frame
- Semi-double cradle aluminium frame
- Gearbox
- 6-speed
- Final drive
- Chain (final drive)
- Clutch
- Multiplate wet clutch
- Front suspension
- KYB® Speed-Sensitive System inverted fork; fully adjustable
- Rear suspension
- KYB® single shock; fully adjustable
- Front wheel travel
- 300 mm (11.8 inches)
- Rear wheel travel
- 315 mm (12.4 inches)
Brakes
- Front brakes
- Single disc. Hydraulic.
- Rear brakes
- Single disc. Hydraulic.
- Front tyre
- 80/100-21
- Rear tyre
- 100/90-19
Dimensions
- Seat height
- 975.00 mm
- Wheelbase
- 1443.00 mm
- Ground clearance
- 366.00 mm
- Length
- 2136.00 mm
- Width
- 828.00 mm
- Height
- 1295.00 mm
- Fuel capacity
- 8.00 L
- Weight
- 93.90 kg
- New price
- 7 499 €
Overview
It’s impossible to talk about motocross without the name Yamaha YZ125 echoing in the paddocks. This machine is more than just a two-stroke; it's a rite of passage, a riding school on dirt. For 2020, the Japanese manufacturer is sticking with continuity and a simple aesthetic update, but it doesn’t matter. When you possess such a pedigree, you don't change a winning formula. The heart of the beast remains this 125cc two-stroke liquid-cooled single-cylinder engine, a true mechanical marvel that develops 40 horsepower for just 94 kilograms fully fueled. These figures promise an electric powerband, a sonic aggressiveness that still makes the knees of even the most seasoned riders tremble.

It must be said that the YZ125 has been shaped by competition. Since its major overhaul in 2015, which gave it this slender and aggressive silhouette, it has constantly been refined. The secret to its effectiveness lies in a surgically precise aluminum chassis, coupled with fully adjustable KYB suspension, inherited directly from the YZ-F four-stroke models. This mechanical base gives it neutrality and track adhesion that make it a formidable weapon. Faced with a KTM 125 SX, often presented as more powerful, the Yamaha opposes reassuring stability and progressivity that appeals to young riders in the making. This is indeed its preferred audience: the teenager aiming for the top of the junior podium, or the amateur rider seeking the most high-performance 125cc motocross bike to perfect their style before moving on to a 250F.
The price of this luxury education? Expect an envelope of around €7499 for the new model. A significant investment, but one in line with a race machine ready to go. For those wondering about homologation, the answer is clear: the YZ125 is a pure competition machine, designed for the track, end of story. Its top speed, although approaching 110 km/h, is just a technical detail; what's important is how it achieves that speed on a circuit. The question "Is the Yamaha YZ125 automatic?" almost elicits a smile, given its demanding handling and short-ratio six-speed gearbox, which require commitment.

For purists and hardened competitors, Yamaha also offers, through its partner YRRD, an impressive catalog of racing parts, from optimized cylinder heads to titanium exhausts. It is in this spirit of absolute performance that the brand will undoubtedly celebrate the 70th anniversary of the Yamaha YZ125. Because beyond the Speed Block graphics and the giant logo on the tank, the soul of this bike remains intact. It is a direct heir to the glorious machines of the 80s and 90s, the original parts of which, sought after by collectors on sites like CMSNL, testify to a valuable technical heritage. Whether you are looking for the value of a 1993 Yamaha YZ125 or the price of a future Yamaha YZ125 Monster Energy 2025, one constant remains: this model embodies the raw and exciting essence of motocross. A two-stroke that refuses to die, and that, year after year, continues to forge champions.
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