Motocross Bikes
2025Yamaha YZ125 Monster Energy
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The 2025 Yamaha YZ125 Monster Energy is a lightweight motocross machine engineered for competitive amateur and intermediate riders seeking aggressive performance. Powered by a potent 125cc two-stroke single-cylinder engine with reed-valve induction, it delivers responsive power delivery and nimble handling ideal for both track racing and off-road training. Known for its proven reliability and affordable entry point into serious motocross competition, the YZ125 remains a class standard for developing rider skills and speed.
- Capacity
- 125.0 ccm
- Engine
- Single, two-stroke
- Gearbox
- 6-speed
- Wet weight
- 96.2 kg
- Seat height
- 980 mm
- Power
- 15.0 HP (11.0 kW)
What’s new for the 2025 Yamaha YZ125 Monster Energy
vs the 2024| Spec | 2024 | 2025 |
|---|---|---|
| Wet weight | 94.8 kg (209.0 pounds) | 96.2 kg (212.1 pounds) |
How it rides
Editorial estimate from the spec sheet - not lab tested- Best for
- Built purely for motocross track riding and competitive off-road racing, not general transportation.
- Built for
- A raw, high-revving two-stroke that rewards aggressive riding, precise clutch control, and active rider input over smooth cruising.
- Not ideal for
- Not suitable for street use, commuting, passengers, or riders seeking comfort and low-maintenance touring capability.
Scores are derived from the spec sheet using the same model across every bike, so they compare like for like.
Will it fit you?
Worked out in your browser - nothing is sent to usEngine
- Capacity
- 125.0 ccm
- Power
- 15.0 HP (11.0 kW)
- Engine type
- Single, two-stroke
- Power/weight ratio
- 0.1559 HP/kg (wet)
- Bore x stroke
- 54.0 x 54.5 mm
- Compression
- 10.1:1
- Cooling system
- Liquid
- Fuel system
- Carburettor
- Starting
- Kick
- Ignition
- CDI
- Lubrication system
- Premix
- Spark plugs
- NGK BR9EVX, NGK BR9EIX
Transmission
- Gearbox
- 6-speed
- Transmission type
- Manual
- Final drive
- Chain
- Clutch
- Multiplate wet clutch
Dimensions & weight
- Wheelbase
- 1445 mm
- Overall length
- 2136 mm
- Overall width
- 826 mm
- Overall height
- 1295 mm
- Seat height
- 980 mm
- Wet weight
- 96.2 kg
- Fuel capacity
- 6.80 litres
- Ground clearance
- 366 mm
- Oil capacity
- 0.70 litres
- Dry weight
- Not on record - add it
Chassis & suspension
- Frame
- Aluminum semi-double cradle
- Front suspension
- KYB® Speed-Sensitive System inverted fork; fully adjustable
- Rear suspension
- KYB® single shock; fully adjustable
- Front wheel travel
- 300 mm
- Rear wheel travel
- 315 mm
- Rake (fork angle)
- 26.0°
- Trail
- 109 mm
- Fork tube size
- 48 mm
Brakes & wheels
- Front brakes
- Single disc. Hydraulic.
- Front brakes diameter
- 270 mm
- Rear brakes
- Single disc. Hydraulic.
- Rear brakes diameter
- 240 mm
- Front tyre
- 80/100-21
- Rear tyre
- 100/90-19
- Brake fluid
- DOT 4
- Tire pressure front
- 15 PSI (1 Bar or 100 kPa)
- Tire pressure rear
- 15 PSI (1 Bar or 100 kPa)
Other
- Color options
- Team Yamaha Blue/green/white
Specs last verified against published sources: .
Compiled from manufacturer documentation and user contributions, corrected on an ongoing basis. Spotted something wrong? Tell us.
What changed, year to year
Differences highlighted| Specification | 2022 | 2023 | 2025 | 2026 | 2027 |
|---|---|---|---|---|---|
| Capacity | 125 cc | 125 cc | 125 cc | 125 cc | 125 cc |
| Dry weight | — | — | — | — | 86 kg |
| Seat height | 980 mm | 980 mm | 980 mm | 980 mm | 980 mm |
| Fuel capacity | 6.8 L | 6.8 L | 6.8 L | 6.8 L | 6.8 L |
Illustrative - generated automatically by diffing the year records already on file, not a manufacturer-published changelog.
Rider Reviews
Common questions
What is the engine size of the Yamaha YZ125 Monster Energy?
The 2025 Yamaha YZ125 Monster Energy has a Capacity of 125.0 ccm (7.63 cubic inches).
What engine power does the Yamaha YZ125 Monster Energy have?
The 2025 Yamaha YZ125 Monster Energy has a Power of 15.0 HP (11.0 kW).
How many gears does the Yamaha YZ125 Monster Energy have?
The 2025 Yamaha YZ125 Monster Energy has a Gearbox of 6-speed.
How much does the Yamaha YZ125 Monster Energy weigh?
The 2025 Yamaha YZ125 Monster Energy has a Wet weight of 96.2 kg (212.1 pounds).
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