2012 Yamaha YZ125

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2012 Yamaha YZ125
2012 Yamaha YZ125

2012 Yamaha YZ125
2012 Yamaha YZ125

2012 Yamaha YZ125
2012 Yamaha YZ125

2012 Yamaha YZ125
2012 Yamaha YZ125

2012 Yamaha YZ125
2012 Yamaha YZ125

– 2012 Yamaha YZ125

2012 Yamaha YZ125 Review

Feed your aggression!

The award-winning, light, nimble two-stroke is more fun than should be allowed on two wheels.

Lightweight, quick and easy to maintain, the 2012 Yamaha YZ125 is a perfect transition from those too big for 85’s but too small or inexperienced for bigger, more powerful 4-strokes.

The secret to going fast is the ability to carry momentum, aggressively but smoothly. Learn it with the YZ125.

For racers looking to make a serious run at motocross success, spend time on a YZ125 two-stroke. Not only does it teach you to be aggressive, but you’ll learn how important it is to maintain a smooth, consistent line around the racetrack. Remember, it’s those who slow down the least that win races. A high revving, quick accelerating engine gets you out of the hole and out of corners on par with any 250 four-stroke, and a plush suspension package delivers confidence in the roughest conditions. The YZ125: a solid foundation for any racing career.

Premix-smells like victory.

Born from the award winning YZ competition bikes, the 2012 Yamaha YZ125 features a light aluminum frame with a powerful, compact engine with awesome power to weight ratio. The 2012 YZ125 is ready to race out of the crate complete with ProTaper aluminum handlebar, titanium footpegs and gripper seat.



2012 Yamaha YZ125 Highlights and Key Features:

Pro Taper Handlebars

6-Speed Transmission

Wave-Style Brake Rotors


Key Features:

•A light aluminum frame housing an amazingly light and compact engine results in an awesome power-to-weight ratio.

•The YZ125 is ready to race out of the crate, complete with a ProTaper® aluminum handlebar, titanium footpegs and gripper seat.

•A pure motocross machine, the light and nimble YZ125 is the perfect choice for riders stepping up from the 85cc class.

•Owning a Yamaha 2-stroke is less expensive to maintain.



2012 Yamaha YZ125 Features and Benefits


Liquid-cooled, 124cc, crankcase reed valve-inducted 2-stroke engine provides class leading power and acceleration and its easy to service too.

7.5-degree cylinder angle and specially designed straight shot intake path through the combustion chamber provide maximum power output.

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.

Specially designed combustion chamber achieves a more complete burn at higher rpms for exceptional power output.

The flat top piston matches the combustion chamber design for maximum power delivery.

In order to reduce frictional losses, the lightweight crank uses special friction reducing crankshaft seals that reduce reciprocating losses for improved power.

Crankcases are both compact and lightweight.

Quick-access, magnesium outer clutch cover is light weight and speeds clutch access.

Close-ratio, 6-speed transmission uses optimized gear ratios to maximize power for outstanding acceleration and corner-exiting 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. The TMXx carb uses a “D” shaped slide design to enhance overall power, while providing crisp throttle response at all rpms.

6-petal, carbon fiber reed design means stronger high-rpm performance with greater over-rev capacity.

Digital CD ignition system delivers a precise spark and monitors engine speed to ensure optimal timing at all rpms for fast, strong response.

Washable, dual-stage, foam air filter reduces maintenance costs.

Large-capacity, dual radiators feature a 10-row core to deliver 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 features a race-spec “barrel adjuster” for on-the-fly clutch adjustments.



Lightweight, aluminum, semi-double-cradle frame combined with the compact engine design, offer an awesome power to weight ratio. The obvious benefit of an aluminum frame is a significant reduction in overall machine weight. Yamaha has maintained the semi-double cradle design because it offers an excellent balance between stiff lateral and torsional rigidity while offering more controlled flex in the longitudinal plane. This frame design offers the ideal “stiffness balance” which means it offers the flexibility of a steel frame with the light weight of an aluminum frame. This frame is made from a unique mix of castings, forgings and extrusions that provide stiffness where it is required and controlled flexibility in other areas. The result is the world’s lightest aluminum MX frame, which provides excellent handling, good ride quality, excellent stability and responsive cornering performance.

Removable rear subframe is constructed of square-section, lightweight aluminum. Detachable design allows easy access when servicing rear suspension components.

Lightweight, tapered design aluminum swingarm is produced using “hydro forming”, a special forming method that uses high pressure water to form shapes.

Cast aluminum upper triple clamp and forged lower triple clamp provide both lightweight and strength for fast, easy handling.

Adjustable handlebar mounts allow the handlebars to be moved 10mm rearward if desired.

“Speed sensitive” 48mm, adjustable, inverted, Kayaba cartridge fork features a twin-chamber design. The 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. Since the inner damper is pressurized, it also eliminates bubbles forming in the oil. The Speed sensitive design means the damping force is controlled by the piston speed in the fork.

The balance between the inner and outer fork tubes has been optimized, while the Kashima coating on the pressure tank and the piston rod reduce friction for smoother suspension performance. The cylinder diameter is 24mm for excellent primary cushioning while low friction oil seals provide reduced stiction for a smoother stroke.

This fork also features a Transfer Control Valve (TCV). The TCV enhances the damping force of the inner damper from mid stroke to full stroke and improves bottoming characteristics. The benefit of TCV is more precise control throughout the full stroke range.

“Kashima coating” is applied to the fork tubes to reduce friction for smoother suspension performance. Front wheel travel is 300mm (11.8″).

Front fork adjustments include: 20-way compression damping and 20-way rebound damping. Optional fork springs are available through Genuine Yamaha parts.

“Wrap-around” plastic fork protectors provide excellent protection from dirt, mud and stone chips. The “self-supporting” design reduces friction for smoother fork operation.

Monocross link rear suspension system features a fully adjustable, Kayaba, piggyback shock which provides 315mm (12.4″) of wheel travel and 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. The damper rod diameter is 18mm in diameter, while Kashima coating is used in the shock body and sub tank to reduce friction and improve suspension performance during a long moto. The Kayaba shock utilizes a full rebound oil lock system for excellent suspension function and great ride quality.

Super lightweight, “Beta” titanium shock spring. This spring reduces weight by over 500 grams versus a conventional steel spring. A reduction in “unsprung” weight causes a dramatic effect on suspension performance. This titanium spring provides outstanding strength, and durability, combined with reduced weight.

250mm floating front disc brake features a “wave” style rotor (disc) which reduces weight, improves cooling and improves styling.

Compact Nissin twin piston front caliper utilizes lightweight aluminum pistons. The braking performance is excellent with great feel and control.

“Shorty” style front brake lever is adjustable for various hand sizes.

245mm rear disc brake with single piston caliper uses an integrated master cylinder (fluid reservoir is integrated into the top of the master cylinder) for strong stopping power with excellent feel and control.

“Wave” style rear rotor (disc) reduces weight, improves cooling and also adds a special styling highlight too.

The rear single piston brake caliper features a rugged plastic caliper protector, while the lower edge of the disc is protected by a lower disc guard.

Specially designed “Sun Star” rear sprocket increases the contact area between the sprocket and chain rollers, thereby reducing the load on the chain and increasing the service life of both chain and sprocket.

Lightweight, 21″ front and 19″ rear rims provide exceptional durability and help reduce unsprung weight for optimal suspension performance and handling.

Pro Taper handlebars with reinforcing crossbar and foam pad provide excellent durability and reduced weight.

Heavy-duty 520 gold anodized “O” ring chain.


“Flat-design” seat features multi density foam that provides good initial softness / comfort and then increases the firmness as more pressure is applied. The “pebble” finish on the top and side surfaces and provides excellent rider grip and durability.

Seat, handlebar and fuel tank ergonomics provide excellent freedom of movement for the rider.

Lightweight, wide titanium footpegs provide excellent grip and ground clearance.

Cleated, rear brake lever and folding shift lever tip offer superb grip and exceptional durability.

Stainless steel, inner clutch cable provides excellent strength, smooth action and long life.

Repackable exhaust silencer means a rider can maintain optimum engine performance and reduced noise levels.

E10 friendly fuel system components


2012 Yamaha YZ125 – USA Specifications/Technical Details
MSRP* $6,290 (Team Yamaha Blue/White) Available from September 2011

Type 124cc, liquid-cooled, 2-stroke, reed-valve inducted
Bore x Stroke 54.0 x 54.5mm
Compression Ratio 8.6~10.7:1
Fuel Delivery Mikuni® TMX 38
Ignition CDI
Transmission Constant-mesh 6-speed; multiplate wet clutch
Final Drive Chain Drive

Suspension / Front Speed-sensitive system inverted fork; fully adjustable, 11.8-in travel
Suspension / Rear Fully adjustable single shock; 12.4-in travel
Brakes / Front Hydraulic single disc brake, 250mm
Brakes / Rear Hydraulic single disc brake, 245mm
Tires / Front 80/100-21-51M
Tires / Rear 100/90-19-57M

Length 84.1 in
Width 32.6 in
Height 51.8 in
Seat Height 39.3 in
Wheelbase 56.8 in
Ground Clearance 15.2 in
Fuel Capacity 2.1 gal
Wet Weight*** 208 lb

Warranty 30 Day (Limited Factory Warranty)



2012 Yamaha YZ125 – Canadian Specifications/Technical Details
Canada MSRP Price: $6,499 CDN


Engine 2-stroke, liquid-cooled, crankcase reed-valve, single
Displacement 124 cc
Bore and Stroke 54.0 x 54.5 mm
Compression Ratio 8.6~10.7:1
Fuel Delivery Mikuni TMX x 38
Ignition / Starting CDI / Kick
Transmission 6-speed
Final Drive Chain


Suspension (Front) Adjustable 48 mm inverted fork / 300 mm (11.8″) travel
Suspension (Rear) Fully adjustable link Monocross / 315 mm (12.4″) travel
Brakes (Front) 250 mm floating disc
Brakes (Rear) 245 mm disc
Tires (Front) 80/100-21
Tires (Rear) 100/90-19

Dimensions / Technical Details

Length 2,139 mm (84.2″)
Width 827 mm (32.6”)
Height 1,318 mm (51.9”)
Wheelbase 1,443 mm (56.8”)
Ground Clearance 388 mm (15.3″)
Seat Height 998 mm (39.3”)
Fuel Capacity 8 litres (1.8 imp. gal)
Wet Weight 94 kg (207 lb)
Colour(s) Yamaha Blue

Specifications, appearance, and price of product are subject to change without notice.

* MSRP does not include freight, PDI (Pre Delivery Inspection), pre-rigging (boats), or taxes. Dealer may sell for less. See your local dealer for out the door pricing.



2012 Yamaha YZ125 – European Specifications/Technical Details
European MSRP Price: NA

Model not available in Europe.

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