THE ONE AND ONLY YZ125.
The ultimate 125 2‑stroke delivers thrilling performance and pure fun.
Lightweight, quick and easy to maintain, the YZ125 is a perfect transition for those too big for 85’s but too small or inexperienced for bigger, more powerful 4-strokes.
Liquid-cooled, 124cc, crankcase reed valve-inducted 2-stroke engine provides class leading power and acceleration. It’s easy to service too!
Ceramic composite cylinder bore is a “liner less” design with the ceramic coating sprayed directly on the aluminum block. The benefits include reduced weight (no heavy iron liner), reduced friction, extended cylinder life and excellent heat dissipation for consistent power delivery.
To make it big in motocross you’ve got to put the hours in at the racetrack. So if you really are serious about getting to the top you’re going to need skill, fitness and determination – and the right race bike.
Which is where the YZ125 comes in. With its explosive engine power and ultra responsive aluminium chassis, this lightweight, 125cc 2-stroke is a proven winner at the highest level.
This legendary dirt bike features ultra responsive front and rear suspension systems for agile handling and fast cornering – and its sharp bodywork gives a cool factory look. Now all that’s missing from the package is…you.
2018 Yamaha YZ125 Totalmotorcycle.com Key Features
- Easy to service, liquid-cooled, 124cc, crankcase reed valve-inducted, 2-stroke engine
- Smooth shifting, 6-speed, close ratio transmission
- Yamaha’s patented YPVS exhaust power valve system
- Lightweight, aluminum, semi-double-cradle frame with detachable rear subframe
- Fully adjustable suspension
- 270 mm front & 245 mm rear disc brakes
- Aluminum handlebar & titanium foot pegs
- Aggressive, modern styling
- 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
- Modern Styling
Modern, aggressive styling, including front fender, front number plate, radiator shrouds, side number plates, air box, rear fender, fork guards, as well as the rear brake disc protector, rear brake caliper protector and wider foot pegs—just like the 4-strokes.
- Lightweight Frame
A light aluminum frame housing a patented YPVS™-equipped ripper of an engine results in an awesome power-to-weight ratio.
- Race-Ready Features
The YZ125 is ready to race out of the crate, complete with an aluminum handlebar, titanium foot pegs and gripper seat.
- Ideal Balance
A pure motocross machine, the light and nimble YZ125 is the perfect choice for riders stepping up from the 85cc class.
- Rider-Friendly Chassis
Ultra light weight means nimble handling with less fatigue.
- 270mm Front Brake
Large 270mm front disc brake coupled with high-performance pad material offers outstanding machine control and performance, with exceptional stopping power and controllability.
2018 Yamaha YZ125 Totalmotorcycle.com Features and Benefits
- Liquid-cooled, 124cc, crankcase reed valve-inducted 2-stroke engine provides class leading power & acceleration.
- super crisp, instant “right now” engine power (when in the “power band”)
- easy & economical to maintain, service & rebuild
- 7.5-degree cylinder angle & straight shot intake path through the combustion chamber.
- maximum power output
- Ceramic composite cylinder bore is a “liner less” 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.
- light weight 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 & 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.
- Mikuni TMXx38 carburetor features a “D” slide design.
- enhances overall power delivery
- provides crisp throttle response at all rpms
- 6-petal, carbon fiber 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 rpms for fast, strong response
- High capacity, washable, dual-stage, foam air filter.
- excellent filtering qualities
- reduces maintenance costs? foam filter is re-useable
- 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 & race-spec “barrel adjuster.”
- easy lever pull
- for on-the-fly clutch adjustments
- 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 & 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 & responsive cornering performance
- Removable rear subframe.
- constructed of square-section, lightweight aluminum
- detachable design allows easy access when servicing rear suspension components
- reduces costs in the event of a loop out
- Lightweight, tapered design aluminum swingarm.
- produced by “hydro forming”, a forming method that uses high pressure water to form shapes
- excellent rear wheel traction & control
- lightweight design
- Cast aluminum upper and forged lower triple clamps.
- strong yet lightweight
- fast, agile handling
- Adjustable handlebar mounts.
- allow handlebar to be moved 10mm rearward if desired
- “Speed Sensitive System” 48mm, adjustable, inverted, “twin chamber” KYB fork. Front wheel travel is 300mm (11.8″).
- fork adjustments include: 20-way compression damping & 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 & 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 & improves bottoming characteristics
- TCV offers more precise control throughout the full suspension stroke
- TCV is located on the upside of the spring & 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 & stone chips
- “self-supporting” design reduces friction for smoother stroke
- Monocross link rear suspension features a fully adjustable, Kayaba, piggyback shock which provides 315mm (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 & 2 turns of high speed compression damping
- 18 mm damper rod
- Kashima coating (friction reducer) is used in the shock body & sub tank to reduce friction & improve suspension performance
- piggyback shock utilizes a full rebound oil lock system for excellent suspension function & 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) & improves styling
- braking performance is excellent with great feel & control
- “Shorty” front brake lever is adjustable for various hand sizes.
- 245mm 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) & improves styling
- strong stopping power with excellent feel & control
- Rugged, plastic rear caliper & lower rear disc protectors / guards.
- “Sun Star” rear sprocket.
- increases the contact area between the sprocket & chain rollers
- reduces the load on the chain & increases service life of chain & sprocket
- Lightweight, D.I.D. 21″ front and 19″ rear rims & premium Dunlop tires.
- provide excellent durability
- reduces unsprung weight for optimal suspension performance & 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 & durability
- Seat, handlebar & fuel tank ergonomics provide excellent freedom of movement for the rider.
2018 Yamaha YZ125 – Totalmotorcycle.com USA Specifications/Technical Details
US MSRP Price: $6,499 USD
Bore x Stroke 54.0mm x 54.5mm
Compression Ratio 8.6~10.7:1
Fuel Delivery Mikuni® TMX 38
Transmission Constant-mesh 6-speed; multiplate wet clutch
Final Drive Chain
Suspension / Front KYB® Speed-Sensitive System inverted fork;
fully adjustable, 11.8-in travel
Suspension / Rear KYB® single shock; fully adjustable, 12.4-in
Brakes / Front Hydraulic disc, 270mm
Brakes / Rear Hydraulic disc, 245mm
Tires / Front 80/100-21 Dunlop® MX52
Tires / Rear 100/90-19 Dunlop® MX52
L x W x H 84.1 in x 32.6 in x 51.0 in
Seat Height 38.4 in
Wheelbase 56.8 in
Rake (Caster Angle) 26.0°
Trail 4.3 in
Ground Clearance 14.4 in
Fuel Capacity 2.1 gal
Wet Weight 207 lb
Warranty 30 Day (Limited Factory Warranty)
Color Team Yamaha Blue
2018 Yamaha YZ125 – Totalmotorcycle.com Canadian Specifications/Technical Details
Canada MSRP Price: $7,049 CDN
2-stroke, liquid-cooled, crankcase reed-valve, single
Bore and Stroke
54.0 x 54.5 mm
Mikuni TMX x 38
Ignition / Starting
CDI / Kick
Adjustable 48 mm inverted fork / 300 mm (11.8″) wheel travel
Fully adjustable link Monocross / 315 mm (12.4″) wheel travel
270 mm floating disc / twin piston caliper
245 mm disc / single piston caliper
2,135 mm (84.1″)
825 mm (32.5”)
1,295 mm (51”)
1,445 mm (56.9”)
365 mm (14.4″)
975 mm (38.4”)
8 litres (1.8 imp. gal)
94 kg (207 lb)
Yamaha Racing Blue
2018 Yamaha YZ125 – Totalmotorcycle.com European Specifications/Technical Details
Europe/UK MSRP Price: £5999 GBP (On The Road inc 20% Vat)
Engine type liquid-cooled, 2-stroke, Forward-inclined single cylinder, reed valve with YPVS
Bore x stroke 54.0 mm x 54.5 mm
Compression ratio 8.6 ~ 10.7 : 1
Maximum power – (
Limited power version – (
Maximum torque –
Lubrication system Premix
Clutch type Wet, multiple-disc coil spring
Fuel system Mikuni TMX38
Ignition system CDI
Starter system Kick
Transmission system Constant Mesh, 6-speed
Final transmission Chain
Frame Semi double cradle
Front suspension system Upside-down telescopic fork
Front travel 300 mm
Caster angle 26º
Trail 109 mm
Rear suspension system Swingarm, (link suspension)
Rear travel 315 mm
Front brake Hydraulic single disc, Ø 250 mm
Rear brake Hydraulic single disc, Ø 245 mm
Front tyre 80/100-21 51M
Rear tyre 100/90-19 57M
Overall length 2,137 mm
Overall width 825 mm
Overall height 1,295 mm
Seat height 975 mm
Wheel base 1,445 mm
Minimum ground clearance 363 mm
Wet weight (including full oil and fuel tank) 94 kg
Fuel tank capacity 8.0 L
Oil tank capacity 0.7 L
Manufacturer Specifications and appearance are subject to change without prior notice on Total Motorcycle (TMW).