Design
The aluminum semi-double-cradle frame in the Yamaha YZ125 is made from a unique mix of castings, forgings, and extrusions that provide stiffness and flexibility, excellent handling, good ride quality, superior stability, and responsive cornering performance. The bike features a specially-designed ’gripper’ type seat and fuel tank, a forward-canted steering crown and a low ProTaper aluminum handlebar, all of which help create greater freedom of movement and more comfortable ergonomics for riders.
The wide, cleated, folding titanium footpegs are lightweight and provide excellent comfort, grip, and ground clearance, as does the prevalent use of light box-head bolts throughout the chassis that eases maintenance while reducing weight for increased performance. The bike’s drive chain comes with gold-colored plates, providing the kind of outstanding looks that make the bike an eye-catching piece of two-wheeled awesomeness.
Engine
Powered by a compact 124cc reed-valve-inducted two-stroke that helps
produce an awesome power-to-weight ratio, the Yamaha YZ125 provides more fun than should be allowed on two-wheels. Joining the engine in the whole mechanical set-up is a patented YPVS power-valve system that combines crisp, hard-hitting bottom-end acceleration with strong midrange and eye-opening top-end, while a 38mm Mikuni TMX carburetor provides adequate throttle response and serious horsepower for riders of all skill levels. There’s also a six-speed, close-ratio transmission which optimizes gear ratios for maximum performance, a digital CDI ignition system delivering precise spark and monitoring engine speed to ensure optimal timing for faster, stronger response during hard acceleration, and a large-capacity radiator that features a 10-row core with four louvers to deliver maximum cooling efficiency at all performance levels.
Brakes and Suspension
The Yamaha YZ125 sports a carefully engineered, advanced aluminum frame and swingarm that gives the bike the best handling in its class. The set-up goes with a Speed-Sensitive System 48mm KYB fork with a damping force that’s controlled by piston speed, providing a smoother, more precise ride than its competitors. There’s also a removable aluminum rear subframe built from square-section tubing for reduced weight, a YZ250F-style front-brake caliper, and wave-style front and
rear discs that minimize unsprung weight and provide excellent
stopping power for the YZ125. Similarly, a fully adjustable KYB rear shock features a super-light titanium shock spring and reduced-friction Kashima coating of internals while separate adjusters for high- and low-speed compression damping, and a full lock oil rebound system for increased comfort all add up to fantastic rear wheel control and a sweet ride.
Specifications
Quote
Motorcycle.com says “this good Motorcross” Who said two-strokes are dead? Well not me, and of course not Yamaha, that’s for sure! With the main focus for development aimed at four-strokes and the other Japanese manufacturers completely terminating their two-stroke line ups, it’s comforting to see Yamaha set aside the time, effort and money to keep this now rare breed of MXer alive. As for myself, having forcefully borrowed Motorcycle.com 2010 YZ125 for a good portion of last year, I have spent plenty of time on this little screamer and was ecstatic to try out the new line. The two-stroke Yamahas took over the four-stroke infested Milestone for the day and brought back some great memories and a whole lot of fun!
gallery: 2011 Yamaha YZ125
