2023 Yamaha YZ125


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.

The liquid-cooled 125cc two-stroke engine has been thoroughly reworked to produce more power than previous generations. Every functional part of the YZ125 engine is new, including the cylinder body, cylinder head, piston, piston pin, connecting rod, crankcase and expansion chamber.

To match increased engine performance, an updated lightweight braking system features larger front pistons, a more rigid caliper, a redesigned 270mm front rotor with a 30% increase in pad contact area and higher friction pad material, all combining to provide exceptional braking power and feel.




Product Description

Increased power and better usability
The MY23 YZ125 retains the most powerful engine ever specified for this model, and it develops a higher performance in the mid to high rpm range and offers improved usability. This has been achieved by developing an all new cylinder head, piston and cylinder, con rod, crank, YPVS as well as redesigning other major components.

Best-in-class KYB suspension
Yamaha’s SSS (Speed Sensitive System) KYB front forks are widely regarded as being amongst the best designs available on a production motocross bike, and this model features optimized low speed damping settings on both the front and rear suspension systems for supreme handling characteristics.

High-efficiency air intake
Following extensive testing Yamaha’s engineers have developed a new intake system. The whole area around the airbox has been redesigned including the seat base, rear frame and side panels in order to reduce air resistance, making a significant contribution towards increased intake efficiency.

Smooth shifting 6-speed transmission
The transmission has been redesigned and features a new set of internals to handle the YZ125’s dramatically increased maximum power output, and a redesigned shift mechanism gives a smoother shift feeling. The secondary reduction ratio is slightly increased with the use of a 13/49 front/rear sprocket set, and for better drivability the transmission runs with slightly reduced 5th and 6th gear ratios.

Engine Type: Liquid-cooled, 2-stroke, reed-valve
Displacement (cc): 125.0
Bore x Stroke (mm): 54.0 x 54.5
Compression Ratio: 8.2 – 10.1 : 1
Lubrication System: Premix
Fuel Management: PWK38S
Ignition: CDI
Starter System: Kick
Fuel Tank Capacity (L): 7.0
Final Transmission: Chain
Transmission: Constant mesh 6-speed

Frame Type: Aluminium controlled filled semi double cradle
Suspension Front: Telescopic forks, 300mm travel
Suspension Rear: Swingarm (link suspension), 315mm travel
Brakes Front: Hydraulic single disc, 270mm
Brakes Rear: Hydraulic single disc, 240mm
Tyres Front: 80/100-21 Bridgestone Battlecross X20F
Tyres Rear: 100/90-19 Bridgestone® Battlecross X20

Length (mm): 2135
Width (mm): 825
Height (mm): 1295
Seat Height (mm): 975
Wheelbase (mm): 1440
Ground Clearance (mm): 365
Wet Weight (kg): 95