Ultra-lightweight YZ125-spec aluminum semi-double cradle frame is engineered to provide the perfect balance of rigidity and flex for competition-ready handling character and composure.
Review – Key Features – Features & Benefits – Specifications
2025 Yamaha YZ125X: THE TWO-STROKE TRAILBLAZER.
Introducing the new 2025 Yamaha YZ125X…
The YZ125X sets the standard for light, fast two-stroke fun! The perfect entry into the world of XC and enduro competition, this two-stroke trailblazer combines thrilling performance and ultimate reliability for all your wins.
TWO‑STROKE TRAILBLAZER
The YZ125X sets the standard for light, fast two‑stroke fun! The perfect entry into the world of XC and enduro competition.
2025 Yamaha YZ125X Totalmotorcycle.com Key Features
- Liquid-cooled 125cc two-stroke engine
- High-precision Hitachi Astemo® Keihin PWK38S carburetor features a power jet, throttle position sensor and 3D-map-controlled CDI unit for precise ignition timing
- Braking system features large front pistons, rigid caliper and a 270mm front rotor
- Model-specific CDI unit
- Racing intake system
- Ultra-lightweight YZ125-spec frame
- Industry-leading, XC-specific adjustable KYB suspension
- Smooth shifting, 6-speed, close ratio transmission
- Powerful New 125cc Two-Stroke Engine
- Improved Fueling
- New Brake System
- Revised Suspension Damping
- Improved Rider Ergonomics
- Bold New YZ Styling
- 18-inch rear wheel and large rear sprocket
- Adjustable, tapered aluminum handlebar
The YZ125’s advanced, liquid-cooled 125cc two-stroke engine provides impressive acceleration, thrilling mid- to high-rpm power, along with supreme usability.
Ultra-lightweight YZ125-spec aluminum semi-double cradle frame is engineered to provide the perfect balance of rigidity and flex for competition-ready handling character and composure.
Cross country focused suspension setup and tires, 18-inch rear wheel, sealed O-ring chain, standard side stand and fuel tank petcock with reserve position all combine to make the perfect GNCC® racer.
2025 Yamaha YZ125X Totalmotorcycle.com Features and Benefits
ENGINE
- Powerful New 125cc Two-Stroke Engine
- A completely redesigned liquid-cooled 125cc two-stroke engine boasts improved usability and increased mid- and top-end power over the 2022 model for a thrilling new level of performance.
- Improved Fueling
- New high-precision Hitachi Astemo® Keihin PWK38S carburetor 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.
- Ceramic composite cylinder bore is a linerless design with the ceramic coating sprayed directly on the aluminum block.
- reduced weight (no heavy iron liner)
- reduced friction
- extended cylinder life
- excellent heat dissipation for consistent power delivery
- Specially designed combustion chamber achieves a more complete burn at higher rpm.
- class-leading power
- Lightweight, flat-top forged aluminum piston.
- excellent durability
- light weight means fast engine response
- matches combustion chamber design for maximum power delivery
- Lightweight, ball-bearing-style crank.
- lightweight design for fast throttle response
- friction-reducing crank seals
- Compact crankcases.
- lightweight design
- helps centralize mass
- Quick-access, magnesium outer (sub) clutch cover.
- lightweight design
- speeds clutch access
- Close-ratio, 6-speed transmission uses optimized gear ratios.
- ratios are matched to engine output for maximum performance
- optimal hook-up for outstanding acceleration and corner-exiting power
- transmission features “involute splines” for smooth, positive shifting even under power
- Yamaha’s patented YPVS system.
- features a slide (guillotine) type power valve that provides the benefits of both solid, low-rpm power delivery combined with a strong top-end punch. This system varies the exhaust port height and timing based on engine rpm.
- 6-petal, carbon fibre reed design.
- for stronger high-rpm performance with greater over-rev capacity
- CD (capacitor discharge) ignition system.
- delivers a precise spark for fast, sure starts
- ensures optimal timing at all rpm for fast, strong response
- High-capacity, washable, dual-stage, foam air filter.
- excellent filtering qualities
- reusable filter reduces maintenance costs
- Large-capacity, dual radiators feature 10-row cores.
- maximum cooling efficiency
- Lightweight exhaust system features a re-packable aluminum silencer which allows the rider/tuner to maintain the correct amount of back pressure for maximum engine performance while reducing noise.
- Works-style clutch lever and race-spec barrel adjuster.
- easy lever pull
- for on-the-fly clutch adjustments
CHASSIS/SUSPENSION
- Lightweight, aluminum, semi-double-cradle frame.
- combines with compact engine to provide an awesome power to weight ratio
- obvious benefit of an aluminum frame is a significant weight reduction
- Yamaha maintains semi-double cradle design because it offers an excellent rigidity balance between lateral and torsional rigidity while offering controlled flex in the longitudinal plane
- result is a light aluminum frame, which provides excellent handling, good ride quality, excellent stability and responsive cornering performance
- Removable rear subframe.
- constructed of square-section, lightweight aluminum
- detachable design allows easy access when servicing rear suspension components
- Lightweight, tapered design aluminum swingarm.
- produced by “hydro forming”, a forming method that uses high pressure water to form shapes
- excellent rear wheel traction and control
- lightweight design
- Cast aluminum upper and forged lower triple clamps.
- strong yet lightweight
- fast, agile handling
- Adjustable handlebar mounts.
- handlebar can be moved 10 mm rearward if desired
- “Speed Sensitive System” 48 mm, adjustable, inverted, “twin chamber” KYB fork. Front wheel travel is 300 mm (11.8″).
- fork adjustments include: 20-way compression damping and 20-way rebound damping
- optional fork springs are available through Genuine Yamaha parts
- low-friction fork seals provide reduced stiction for a smoother stroke
- twin-chamber design means the damper unit is in a separate structure which prevents aerated fork oil from entering the inner damper assembly and degrading its damping abilities
- the inner damper is pressurized, it also eliminates bubbles forming in the oil
- “Speed Sensitive” design means the damping force is controlled by piston speed, not position in the fork
- Fork also features a Transfer Control Valve (TCV).
- TCV enhances damping from mid to full stroke and improves bottoming characteristics
- TCV offers more precise control throughout the full suspension stroke
- TCV is located on the upside of the spring and its function is controlled by piston speed, not piston position, hence the term “Speed Sensitive System fork”
- Large wrap-around plastic fork protectors.
- provide excellent protection from dirt, mud and stone chips
- self-supporting design reduces friction for smoother stroke
- Monocross link rear suspension features a fully adjustable, KYB piggyback shock which provides 315 mm (12.4″) of wheel travel.
- features separate adjusters for high- and low-speed compression damping
- adjustments include: spring preload, 20-way rebound damping, 20-way low-speed compression damping and 2 turns of high speed compression damping
- 18 mm damper rod
- Kashima coating (friction reducer) is used in the shock body and sub tank to reduce friction and improve suspension performance
- piggyback shock utilizes a full rebound oil lock system for excellent suspension function and great ride quality.
- 270 mm floating front disc brake with Nissin twin piston caliper.
- “wave” style rotor (disc) reduces weight, improves cooling (more surface area) and improves styling
- braking performance is excellent with great feel and control
- “Shorty” front brake lever is adjustable for various hand sizes.
- 245 mm rear disc brake with single piston caliper.
- integrated master cylinder (fluid reservoir is integrated into the top of the master cylinder)
- “wave” style rotor (disc) reduces weight, improves cooling (more surface area) and improves styling
- strong stopping power with excellent feel and control
- Rugged, plastic rear caliper and lower rear disc protectors / guards.
- Sun Star-brand rear sprocket.
- increases the contact area between the sprocket and chain rollers
- reduces the load on the chain and increases service life of chain and sprocket
- Lightweight, D.I.D. 21″ front and 18″ rear rims and premium Dunlop tires.
- provide excellent durability
- reduces unsprung weight for optimal suspension performance and handling
- Flat-design seat features multi-density foam.
- provides good initial softness/comfort and then increases the firmness as more pressure is applied
- “pebble” finish on the top and side surfaces provides excellent rider grip and durability
- Seat, handlebar and fuel tank ergonomics provide excellent freedom of movement for the rider.
DETAILS
- Cross Country Ergonomics
- A racy “gripper”-type seat and narrow fuel tank combined with a tapered aluminum handlebar and adjustable mounts create greater freedom of movement and more comfortable ergonomics for riders.
- Cross Country Features
- The YZ125X is focused on enduro competition with an 18-inch rear wheel, larger rear sprocket, side stand, sealed O-ring chain, reserve fuel petcock, and newly adopted scraper between the fork’s dust and oil seal, all adding up to exceptional cross country performance.
- Slim design, modern aggressive bodywork allows easy rider movements
- Lightweight YZ250F/450F-based wide footpegs provide excellent grip & ground clearance
- Heavy-duty 520 gold anodized “O” ring chain
- Rugged chain guide helps prevent the chain from de-railing & also helps protect the rear sprocket
- Serrated rear brake lever & folding shift lever tip
- Stainless steel, inner clutch cable provides excellent strength, smooth action & long life
- E10 friendly fuel system components
2025 Yamaha YZ125X – Totalmotorcycle.com USA Specifications/Technical Details
US MSRP Price: $7199 USD
Canada MSRP Price: $8,399 CDN
Europe/UK MSRP Price: £ NA GBP (On The Road inc 20% Vat)
ENGINE
| Engine Type | 125cc liquid-cooled 2-stroke; reed-valve inducted |
| Bore x Stroke | 54.0 mm x 54.5 mm |
| Compression Ratio | 7.8~10.2:1 |
| Fuel Delivery | Hitachi Astemo® Keihin PWK38S |
| Transmission | 6-speed; multiplate wet clutch |
| Final Drive | Chain |
| Fuel Capacity | 1.8 gal |
CHASSIS
| Suspension/Front | KYB® Speed-Sensitive System inverted fork; fully adjustable, 11.8-in travel |
| Suspension/Rear | KYB® single shock; fully adjustable, 12.4-in travel |
| Brakes/Front | Hydraulic disc, 270mm |
| Brakes/Rear | Hydraulic disc, 240mm |
| Tires/Front | 80/100-21 Dunlop® Geomax MX33F |
| Tires/Rear | 110/100-18 Dunlop® Geomax MX33 |
DIMENSIONS
| LxWxH | 84.8 in x 32.5 in x 50.8 in |
| Seat Height | 38.2 in |
| Wheelbase | 57.3 in |
| Rake (Caster Angle) | 26.4° |
| Trail | 4.4 in |
| Max. Ground Clearance | 14.0 in |
| Fuel Capacity | 1.8 gal |
| Wet Weight*** | 212 lb |
OTHER
| Warranty | 30 Day (Limited Factory Warranty) |
*Manufacturer’s Suggested Retail Price (MSRP) shown. Does not include tax, title, prep or destination charges. Actual prices set by dealer.
**Fuel Economy is estimated.
***Wet weight includes the vehicle with all standard equipment and all fluids, including oil, coolant (as applicable) and a full tank of fuel. It does not include the weight of options or accessories. Wet weight is useful in making real-world comparisons with other models.
2025 Yamaha YZ125X – Totalmotorcycle.com Canada Specifications/Technical Details
ENGINE
ENGINE 2-stroke, liquid-cooled, reed-valve, single
DISPLACEMENT 125 cc
BORE AND STROKE 54.0 x 54.5 mm
COMPRESSION RATIO 7.8~10.2:1
FUEL DELIVERY Hitachi Astemo® Keihin PWK38S
IGNITION / STARTING CDI / Kick
TRANSMISSION Constant mesh, 6-speed
FINAL DRIVE Chain
CHASSIS
SUSPENSION (FRONT) Fully adjustable 48 mm KYB inverted fork / 300 mm (11.8″) travel
SUSPENSION (REAR) Fully adjustable KYB link Monocross / 315 mm (12.4″) travel
BRAKES (FRONT) 270 mm floating disc / twin piston caliper
BRAKES (REAR) 240 mm disc / single piston caliper
TIRES (FRONT) 80/100-21
TIRES (REAR) 110/100-18
CRITICAL DATA
LENGTH 2,154 mm (84.8″)
WIDTH 825 mm (32.5″)
HEIGHT 1,290 mm (50.8″)
WHEELBASE 1,455 mm (57.3″)
GROUND CLEARANCE 356 mm (14″)
SEAT HEIGHT 970 mm (38.2″)
FUEL CAPACITY 8 litres (1.8 imp. gallons)
WET WEIGHT 96 kg (212 lb)
COLOUR(S) Team Yamaha Blue
2025 Yamaha YZ125X – Totalmotorcycle.com European Specifications/Technical Details
NA
Manufacturer Specifications and appearance are subject to change without prior notice on Total Motorcycle (TMW).
