YZ450F

The bike that started the four-stroke revolution is back with some changes for next year, mostly from chassis refinements. Subtle modifications to the suspension improve handling, and head and exhaust design delivers stronger low-to midrange power without sacrificing top end power.

Features include a ProTaper aluminum handlebar in adjustable clamps, titanium shock spring, gripper seat and Excel rims. A five-speed gearbox provides maximum flexibility and the right gear for a wide range of riding environments. Dry sump lubrication system circulates more oil for durability.

NEW FOR 2009 Top triple clamp has two sets of mounting holes, providing four handlebar positions to suit a wide variety of riders: standard, 10mm back, or 10mm, or 20mm forward.

Newly designed swingarm is lighter and helps rigidity balance for improved cornering and rear wheel traction. Lightweight suspension linkage is redesigned to match the new swingarm. New rear wheel hub is lighter and designed for the larger 25mm diameter axle (up from 22mm), helping to achieve the overall rigidity balance of rear suspension components. New clutch lever is shorter, stronger, and lighter, with a lever position adjuster to accommodate different riders. Quick adjuster makes maintenance easy. Front brake hose clamp is now aluminum, greatly reducing its weight.

New seat cover has great grip and more durability, and it’s easy to clean. Premium drive chain has gold colored plates for outstanding looks.

ENGINE 449cc, five-valve, DOHC, liquid-cooled engine is powerful, yet tractable. 39mm Keihin FCR flat-slide carburetor with throttle position sensor (TPS) and leak jet delivers precise fuel/air mixture and instant throttle response. Lightweight titanium valves and load-reduced springs minimize reciprocating mass. Primary kickstarting with automatic decompression and convenient, handlebar-mounted hot start lever. Large-capacity radiator is reinforced for greater strength.

CHASSIS Extensively tested aluminum frame uses a mix of alloy castings, forgings and extrusions to produce a tuned-flex frame. Speed-Sensitive System 48mm KYB fork damping force is controlled by piston speed and provides a smoother, more precise ride. Titanium-sprung, four-way adjustable rear shock with Kashima-coated internals reduces friction. More weight savings come via two-piece (part aluminum, part plastic) engine protector plates and thin-walled engine guard construction. Removable aluminum rear subframe constructed of square-section tubing for light weight and easy maintenance. Lightweight front-wheel hub for reduced unsprung weight and increased durability. Lightweight front- and rear-brake calipers with aluminum pistons and anti-bubble front master cylinder; wave-style rotors reduce unsprung weight and deliver strong stopping power.

ADDITIONAL FEATURES Wide (55mm) footpegs provide excellent boot traction and rider comfort. ProTaper aluminum handlebar for strength and performance. Works-style clutch lever features oversize barrel adjuster for easy, on-the-fly adjustability of lever/cable play. Repackable exhaust silencer.

MSRP* $7,399 (Team Yamaha Blue/White) Available from July 2008 $7,499 (White/Red) Available from July 2008

YZ250

One of the few remaining two-stroke motocrossers, the YZ250 has a light, aluminum frame, housing a patented YPVS® Power valve-equipped engine. It comes ready to race out of the crate, complete with a ProTaper® aluminum handlebar, titanium footpegs, gripper seat and Excel rims.

NEW FOR 2009 Dunlop D742A front tire has an innovative knob pattern for excellent grip and handling. New seat cover has great grip and more durability, and it’s easy to clean. Premium drive chain has gold colored plates for outstanding looks. Front brake hose clamp is now aluminum, greatly reducing its weight.

ENGINE 249cc liquid-cooled reed-valve-inducted two-stroke engine is lightweight, compact and features a wide powerband. Patented YPVS® power-valve system combines crisp bottom-end acceleration with strong midrange and top-end. Special-design carbon fiber reed-valve petals improve throttle response and engine performance across the entire rpm range.

Smooth-shifting, five-speed, close-ratio transmission with heavy-duty, multiplate clutch. Primary kickstarter ensures smooth, easy starting action and reduced weight. Large-capacity radiator features a ten-row core with four louvers for maximum cooling efficiency. 38mm Keihin® PWK carburetor with power jet and throttle position sensor (TPS) ensures precise fuel/air mixing and extra-crisp throttle response throughout the powerband. Digital CDI ignition system delivers precise spark. Works-style clutch lever features race-spec barrel adjuster for on-the-fly adjustability.

CHASSIS YZ250F-style front-brake caliper and wave type front and rear discs minimize unsprung weight and provide excellent stopping power. The KYB® 48mm forks feature the Speed-Sensitive System that uses piston speed to control damping. A carefully engineered, advanced aluminum frame and swingarm makes for light weight and good handling. Removable aluminum rear subframe constructed of square-section tubing for reduced weight. Rear, fully adjustable KYB® shock features a super-light titanium shock spring and reduced-friction Kashima coating of internals. 12.4 inches of travel, separate adjusters for high-and low-speed compression damping, and a full lock oil rebound system for increased comfort. Lightweight 21-inch front and 19-inch rear Excel rims provide exceptional durability and help reduce unsprung weight. Tapered rear wheel spacers ease sliding the rear wheel into place for quicker tire changes. Premium Dunlop® knobbies offer race-spec traction and wear.

ADDITIONAL FEATURES Wide, cleated, folding titanium footpegs are lightweight and provide excellent comfort, grip, and ground clearance. Special-design “gripper” type seat and fuel tank, forward-canted steering crown and low handlebar provide excellent movement and more comfortable ergonomics for riders. Wide-diameter fuel tank cap ensures easier usage, while larger tank opening means faster, hassle-free refueling. Wide-diameter fuel tank cap ensures easier usage, while larger tank opening means faster, hassle-free refueling. Use of light, box-head bolts throughout the chassis eases maintenance, while reducing weight and increasing performance. Repackable exhaust silencer. Durable, comfortable handlebar grips.

MSRP* $6,599 (Team Yamaha Blue/White) Available from June 2008

YZ250F

The high-revving “F” model has a five-titanium-valve engine with 13.5:1 compression ratio and spins out great torque and horsepower. A carefully tuned aluminum frame made up of forgings, weldings, castings and tubing is state of the art. Mass centralization provides overall balance and performance. A ProTaper® aluminum handlebar in adjustable clamps and Excel rims are standard. Dry sump lubrication system circulates more oil for durability.

NEW FOR 2009 Redesigned exhaust system has a 60mm longer titanium header for better low-end grunt, plus a 50mm shorter aluminum silencer for optimum low-rpm throttle response. Both carburetor jetting and CDI ignition mapping settings are precisely reworked to deliver increased engine performance with new exhaust. New clutch eliminates the judder spring and uses a floating rubber damper instead of a coil spring to provide improved clutch performance. The clutch eliminates the judder spring and uses a floating rubber damper instead of a coil spring. Newly designed swingarm is lighter and helps to achieve excellent rigidity balance. Lightweight suspension linkage is redesigned to match the new swingarm. New rear wheel hub is lighter and designed for the larger 25mm diameter axle (up from 22mm), helping to achieve the overall rigidity balance of rear suspension components. New clutch lever is shorter, stronger, and lighter, with a lever position adjuster to accommodate different riders. Quick adjuster makes maintenance easy. Front brake hose clamp is now aluminum, reducing its weight. New seat cover has great grip and more durability, and it’s easy to clean. Premium drive chain has gold colored plates for outstanding looks.

ENGINE Liquid-cooled 250cc, five-titanium-valved, DOHC, four-stroke is powerful and highly tractable. 37mm Keihin® FCR flat-slide carburetor with throttle position sensor (TPS) ensures precise fuel/air mixing and quick throttle response. Cylinder body and crankcase feature a large cutaway section to reduce pumping loss and increase midrange performance. Primary kickstarting (with automatic decompression and convenient handlebar-mounted hot start lever) ensures easy restarts. Five-speed transmission with heavy-duty, multiplate clutch features an involute spline setup, ensuring smooth shifting and instant hookup under power. Magnesium cylinder head cover, now covered matte black, helps shave weight. Works-style clutch lever features race-spec barrel adjuster for on-the-fly adjustability.

CHASSIS Aluminum frame uses a mix of alloy castings, forgings and extrusions to produce a tuned-flex frame. Speed-Sensitive System 48mm KYB® fork damping force is controlled by piston speed: provides a smoother, more precise ride. Four-way adjustable, rear shock with Kashima-coated internals reduces friction. Removable aluminum rear subframe is constructed of square-section tubing for light weight and easy maintenance. Lightweight front wheel hub for reduced unsprung weight and increased durability. Lightweight front and rear brake calipers with aluminum pistons and anti-bubble front master cylinder; wave-style rotors reduce unsprung weight and deliver strong stopping power. Lightweight 21-inch front and 19-inch rear Excel rims are exceptionally durable and reduce unsprung weight.

MSRP* $6,549 (Team Yamaha Blue/White) Available from July 2008; $6,649 (White/Red) Available from July 2008

YZ125

Another one of the few remaining two strokes, the YZ125 has an aluminum frame, housing a light and compact engine. It’s ready to race out of the crate, complete with a ProTaper aluminum handlebar, titanium footpegs and gripper seat.

NEW FOR 2009 Dunlop® D742FA front tire has an innovative knob pattern for excellent grip and handling. New seat cover has great grip and more durability, and it’s easy to clean. Premium drive chain has gold colored plates for outstanding looks. Front brake hose clamp is now aluminum, reducing its weight.

ENGINE Reed-valve spacer improves acceleration across the entire powerband. Compact 124cc reed-valve-inducted two-stroke has a patented YPVS® power-valve system. 38mm Mikuni TMX carburetor gives excellent throttle response. Six-speed, close-ratio transmission optimizes gear ratios. Digital CDI ignition system delivers precise spark and monitors engine speed to ensure optimal timing for faster, stronger response during hard acceleration. Primary kickstarting ensures easy restarts in any gear. Works-style clutch lever features race-spec barrel adjuster for on-the-fly adjustability.

CHASSIS YZ250F-style front-brake caliper and wave type front and rear discs minimize unsprung weight and provide excellent stopping power. Speed-Sensitive System 48mm KYB® fork damping force is controlled by piston speed. Removable aluminum rear subframe constructed of square-section tubing for reduced weight. Rear, fully adjustable KYB® shock features a super-light titanium shock spring and reduced-friction Kashima coating of internals. 12.4 inches of travel, separate adjusters for high- and low-speed compression damping, and a full lock oil rebound system. Tapered rear wheel spacers ease sliding the rear wheel into place for quicker tire changes. Premium Dunlop® knobbies offer race-spec traction and wear. Special-design “gripper” type seat and fuel tank, forward-canted steering crown and low ProTaper handlebar all help create greater freedom of movement.

ADDITIONAL FEATURES Wide, cleated, folding titanium footpegs are lightweight and provide excellent comfort, grip, and ground clearance. Use of light, box-head bolts throughout the chassis eases maintenance while reducing weight for increased performance. Wide-diameter fuel tank cap for easier refueling. Repackable exhaust silencer. Durable, comfortable handlebar grips.

MSRP* $5,799 (Team Yamaha Blue/White) Available from June 2008

YZ85

All of the mini-motocrossers are still two strokes, and the YZ85 is no exception. It’s liquid-cooled, 84.7cc crankcase reed-valve-inducted and has a six-speed gearbox. Ultra-rigid, single-backbone, semi-double-cradle frame is lightweight and strong for sharp handling. Fully adjustable suspension allows a broad adjustment range to suit everybody from rank novice to mini expert.

ENGINE 84.7cc liquid-cooled, crankcase reed-valve-inducted, two-stroke engine inhales through a 28mm Keihin® flat-slide carburetor. Digital CDI ignition system puts out a more precise spark and monitors engine speed to ensure optimal timing for quicker, stronger response during hard acceleration. Smooth-shifting, six-speed close-ratio transmission with heavy-duty, multiplate clutch delivers maximum hookup. Involute spline set-up in clutch means smoother shifting under power with great durability at competition-level usage. Two-piece clutch cover provides easy access during maintenance. Lightweight radiator has large cores and louvers, and the water pump features a cast aluminum (vs. resin) impeller for maximum cooling efficiency. Lightweight exhaust system design helps create a broader powerband with stronger low-end punch. Airbox design ensures greater air cleaning performance and easier maintenance.

CHASSIS Rear subframe is removable to allow easy maintenance. Lightweight 36mm KYB® inverted cartridge fork features 10.8 inches of travel with compression and rebound damping adjustability, and low-friction outer tubes and internals. Rear suspension features fully adjustable Kayaba link-type shock with 11.1 inches of travel and race-tested compression damping valving. 220mm front disc and 190mm rear disc brakes with stainless steel rotors deliver strong, precise stopping power. Lightweight 17-inch front and 14-inch rear rims are durable and reduce unsprung weight. Dunlop® knobbies provide great traction on a variety of tracks and terrain.

ADDITIONAL FEATURES Wide handlebar and flat fuel tank, radiator shrouds, side panels and rear fender provide rider with leverage and freedom of movement and weight transfer. Wide footpegs provide superb comfort, grip and ground clearance. Separate clutch cover with transmission oil filler opening makes for easy maintenance. Fuel tank cap is wider-diameter for easier usage, and large tank opening ensures fast, hassle-free refueling. Repackable exhaust silencer.

MSRP* $3,349 (Team Yamaha Blue/White) Available from August 2008