Introducing the new 2010 Yamaha YZ250F. The key development concept behind this awesome new machine is excellent cornering and handling performance. In other words, the new 2010 YZ250F “does exactly what the rider wants”.

The year was 2001 and Yamaha introduced the first modern 250cc 4-stroke motocrosser. We have taken the original concept of “Ultimate Quick Turn Performance” and elevated it to an entirely new level.

The all new Bilateral Beam aluminum frame centralizes mass for exceptional cornering and handling performance. The 250F is more compact than the pervious generation chassis for superior cornering. The optimized engine delivers a new level of power in the low-to-midrange, with a great torquey feel, exactly where riders want it. Mix in improvements to the intake and exhaust system, lighter valve train, new carburetor settings and you have a winning combination that will be hard to beat.

Key Features

•  The all-new, Bilateral Beam frame is specific to the 250 and is more compact than the previous generation chassis. This places the rider closer to the front wheel, which delivers superb rigidity balance for unmatched lightweight handling and cornering. This nimbleness lets the rider get on the gas sooner out of corners and cross the finish line with less fatigue – even on long motos.

•  The optimized engine delivers a new level of power in low-to-midrange, with a great torquey feel, exactly where riders want it. That is due to the new straight intake boot that enhances breathing, new carburetor that provides excellent throttle response and fuel atomization, and redesigned valve train components that reduce inertial mass and boost low end torque. Exhaust is also enhanced with a new D-shaped exhaust port and newly designed exhaust system. Ongoing refinement to the suspension and engine produces an amazingly balanced, light-handling machine with performance that’s accessible to all levels of riders.

•  All new styling emphasizes the bike’s light weight and nimble handling character. The sharp, horizontal lines set the bike apart, with a clean, aggressive look.
KYB® suspension has been recalibrated front and rear and is tuned to work with the new Bilateral Beam frame for unmatched handling. The clutch lever has a lighter pull feel even though the clutch has stronger engagement. The new clutch also has a wider engagement range that will give riders an advantage off the line. . . shift after shift, moto after moto.

•  There’s no disputing the YZ250F’s unmatched four-stroke prowess – it was the 1st four-stroke 250 motocross bike on the market, the 1st to win an international race, the 1st to win an AMA® Supercross ® and the 1st to take an AMA® U.S. Supercross Championship® title, as well as the first to win an AMA® National race.

Features and Benefits

•  For 2010 the YZ engineers have focused on optimizing the intake & exhaust systems, lightened the valve train, revised the carburetor settings and improved the ignition advance characteristics. These improvements result in improved low to mid power and a more rider friendly engine with a more linear power delivery for improved drivability and control.

•  New, liquid-cooled, 250cc, DOHC, 5-titanium valve, 4-stroke engine features a 13,500-rpm redline.

•  Short skirt forged piston reduces weight and vibration, plus offers excellent durability.

•  The 13.5:1 compression ratio provides fast, controlled combustion and excellent engine performance.

•  Optimized 5-valve (3-intake & 2-exhaust) combustion chamber design provides the most efficient intake and exhaust flow for maximum power.

•  Titanium valves decrease weight by more than 40% over a conventional steel valve train and reduce reciprocating mass for faster-revving.

•  All new aluminium valve retainers reduce inertial mass for faster throttle response

•  New “load reduced” valve springs reduce the amount of force required to open the valves and thereby minimizes power losses associated with friction and improves torque in the low and mid ranges.

•  Special chromium nitride coating on the tips of the intake valve stems reduces wear.

•  Exhaust port shape has been revised from a round to a “D” shape to optimize flow and improve performance and engine character

•  Revised intake cam profile further improves performance.

•  The lightweight “liner less” aluminium cylinder features a ceramic composite coating which insures faster, more uniform heat dissipation, reduced friction and a longer service life.

•  Cylinder design features cutaways that allow the air trapped under the piston to enter a side chamber (or cutaway) to reduce horsepower-robbing “pumping losses.”

•  Revised lightweight engine crankcase also utilizes special cutaways to reduce “pumping losses.” The crankcase cutaways match the cutaways in the cylinder for maximum efficiency.

•  Relocated convenient oil sight glass window and oil drain plug.

•  Lightweight magnesium cylinder head cover.

•  Dry sump lubrication system uses a remote oil tank reservoir positioned in front of the engine. This revised oil tank is lighter and more compact for 2010 and features a partition in the centre of the tank that improves the air-oil separation function. This tank is positioned low in the chassis which centralizes mass and lowers the centre of gravity for exceptional handling and a light feeling.

•  Oil volume in the engine has been optimized to reduce weight and “oil drag” related power losses.

•  Revised, 5-speed transmission features “involute splines” on the transmission axles to ensure smooth shifting and instant hook-up under power. The gear ratios for 3rd and 4th gears and the engagement dog shape have been changed to maximize the engine improvements. 3rd gear ratio = 26/18(1.444) while 4th gear ratio is 22/18(1.222).

•  Lightweight engine counterbalancer reduces vibration for improved rider comfort and less rider fatigue.

•  Revised multi-plate wet clutch features a revised clutch boss insert for improved wear, clutch spring load has been increased and the length of the push lever cam has been revised to change the lever ratio for an easier clutch lever pull and improved clutch feeling.

•  Lightweight, “quick-access” outer clutch cover provides fast, easy access for clutch maintenance.

•  Compact design automatic cam chain tensioner reduces maintenance and mechanical engine noise

•  Revised Keihin FCR-MX37 flat-slide carburetor with throttle position sensor (TPS). The carb settings have been revised to accentuate the improvements in the intake and exhaust systems. The cam for the accelerator pump has been optimized while the shape of the carburetor “throat” on the air box side has been modified for improved air flow.

•  The air box assembly has been revised for improved performance. The funnel shape at the air box “outlet” is optimized, while an all new straight design “boot” between the air box and the carb also improves air flow.

•  Washable, dual-stage, foam air filter.

•  No fuss auto decompression system means fast, easy starting. The YZ250F restarts in any gear.

•  Convenient, handlebar-mounted hot start lever ensures fast starts when the engine is hot.

•  Revised CD ignition system delivers a precise spark and monitors engine rpm to insure optimal timing for fast, strong response at all rpms. The ignition timing advance curve has been revised for improved performance.

•  Direct ignition system means the ignition coil is integrated into spark plug cap to reduce weight and complexity.

•  New compact, lightweight, single core, dual radiators provide outstanding cooling efficiency. The location of the rads has been lowered and moved rearward for improved performance and protection while also lowering the all important center of gravity and centralizing mass. The thickness of the cores has also been increased. For 2010, the revised rads mount to the new frame at 3 points.

•  Lightweight titanium exhaust header pipe reduces weight, improves performance and allows hassle-free replacement of the oil filter.

•  The lightweight exhaust system utilizes a 4-stage expansion format that improves the cylinder filling induced by the exhaust pulse effect, resulting in excellent power characteristics.

•  Revised rigid mount muffler assembly is 50mm longer than last year for improved performance and reduced noise levels. The size of the internal diffuser pipe and the noise reducing “punched hole pipe” have been modified to achieve optimum performance.

•  The muffler can be repacked to maintain peak performance and reduced noise. The lightweight aluminium / stainless steel muffler complies with current CMRC & AMA noise regulations for 2010.

•  Trick, oversized “barrel adjuster” on the clutch lever perch allows on-the-fly clutch adjustments.

Chassis/Suspension

•  All new, compact “bilateral beam” aluminium frame centralizes mass for exceptional handling and cornering ability. This 250cc class specifically designed frame consists of forged, extruded and panel aluminium parts. This all new frame is more compact than the last generation and offers significantly improved “rider – machine communication” (a.k.a. feedback). The key goal of this new chassis is faster and easier cornering … one of the keys to winning races.

•  The engineers started with a clean sheet of paper and designed the chassis based on the requirements of a 250cc motocrosser. Note: the YZ250F frame is unique unto itself.

•  The rigidity balance of this new frame has been optimized and features increased lateral and torsional rigidity compared to the last generation frame. It also contributes to a feeling of lightness, agility and traction.

•  The head pipe (steering head), wheelbase, caster and trail dimensions are optimized to accentuate the new engine and frame character. The benefit is incredible turning ability and quick, stable handling.

•  New removable rear sub frame is constructed of square-section, lightweight aluminium pipe. Its detachable design allows easy access when servicing rear suspension components.

•  Lightweight, tapered, aluminium swingarm is produced using “hydro forming”, a special method that uses high pressure water to form shapes. The swingarm design provides great overall chassis “balance” for precise cornering and a light handling feel.

•  Forged aluminium upper triple and lower triple clamps reduces weight and improve strength.

•  Pro Taper handlebars are one of the most sought after style of bars. The Pro Taper bars provide excellent strength and durability. Foam handlebar pad is included.

•  Handlebar position has been raised 5mm for 2010 to suit the new, more compact frame. The revised handlebar holders (with the upper triple clamp), offer a total of 4 different positions, and an adjustment range of 30mm, to better suit a wide variety of riders.

•  Revised 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 prevents air bubbles forming in the oil. Front fork adjustments include: 20-way compression damping and 20-way rebound damping.

•  Optional fork springs are available through Genuine Yamaha parts.

•  Fork damping settings have been revised for 2010. The shape of the outer fork tubes, the inner piston rod design, and the low friction fork oil seals are also revised. The engineers focused on the enhancing the ground holding capabilities of the front wheel, a key for precise cornering.

•  The 48mm inverted KYB fork also features a Transfer Control Valve (TCV) system. 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. The 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 fork”.

•  Front wheel travel is 300mm or 11.8″

•  Revised, large “wrap-around” plastic fork protectors provide excellent lower fork tube protection. The “self-supporting” design reduces friction for smoother fork operation.

•  Revised Monocross link rear suspension system features a fully adjustable Kayaba, piggyback shock which 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 shock spring location has been lowered 29mm to accommodate the new intake boot.

•  The shock uses an 18mm diameter piston rod. 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.

•  Rear wheel travel is 307mm (12.1″).

•  250mm floating front wave-style disc reduces weight and is squeezed by a Nissin twin piston caliper.

•  245mm rear disc brake features a lightweight “wave-style” disc and a single piston Nissin caliper.

•  Compact and lightweight rear master cylinder is an integrated design (fluid reservoir is integrated into the top of the master cylinder) for strong stopping power with excellent feel and control.

•  Newly designed rear pedal tucks in tighter to the engine / frame and reduces weight.

•  Newly designed, compact body work includes front number plate, front fender, rad shrouds, fuel tank, side panels and rear fender
which enhance the lightweight feel and look of the new YZ250F. This new “minimal ” bodywork is a flat design, allowing fast, easy rider movements. The ergonomics provide a natural and roomy riding position. The body has been designed to maintain it good looks throughout the life of the machine.

•  The lightweight, plastic resin 6.4 litre fuel tank compliments the chassis and has been moved closer to the rider for centralization of fuel tank mass and compactness.

•  Redesigned seat is unique to the 250F. The surface texture has been designed to give a grip when needed, yet still allow easy rider movements. The “gripper” style seat cover has been designed to resists clogging with dirt or mud to ensure long lasting good looks.

•  New lightweight Sun Star rear sprocket.

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

•  Rear wheel assembly uses a large 25mm diameter axle and a rear hub design which features a second bearing on the sprocket side for increased rigidity and durability.

•  Bridgestone knobby tires offer competition-spec traction and excellent wear. Front = M403 / rear = M404.

Details

•  All new rugged polypropylene engine and integrated water pump protector plate reduces weight.

•  “Shorty” adjustable front brake lever. Adjustment range is 5.5mm.

•  New heavy duty plastic rear caliper and lower rear disc protectors.

•  Large fuel cap and filler hole ensures easy opening and fast, hassle-free refuelling.

•  New lightweight, extra wide foot pegs are 5mm higher and provide excellent grip and improved rider comfort.

•  Lightweight header pipe heat shield.

•  Serrated rear brake pedal for extra grip.

•  Folding gear shifter tip.

•  Stainless steel inner clutch cable provides excellent strength and durability.

•  Lightweight chain guide / support helps reduce chance of chain derailment. It also helps protect rear sprocket from damage too.

•  Heavy duty rubber swingarm protector.

•  Heavy duty DID 520 drive chain.

USA Specifications

MSRP*$7,090 (White/Red) Available from September 2009
$6,990 (Team Yamaha Blue/White) Available from September 2009

Engine

Type: 250cc liquid-cooled DOHC 4-stroke; 5 titanium valves

Bore x Stroke: 77.0mm x 53.6mm

Compression Ratio: 13.5:1

Fuel Delivery: Keihin® FCR MX37

Ignition: CDI

Transmission: Constant-mesh 5-speed; multiplate wet clutch

Final Drive: Chain Drive

Chassis

Suspension/Front: Speed-Sensitive System inverted fork; fully adjustable, 11.8-in travel

Suspension/Rear: Fully adjustable single shock; 12.0-in travel

Brakes/Front: Hydraulic single disc brake, 250mm

Brakes/Rear: Hydraulic single disc brake, 245mm

Tires/Front: 80/100-21

Tires/Rear: 110/90-19

Dimensions Length: 85 in

Width: 32.5 in

Height: 51.3 in

Seat Height: 38.9 in

Wheelbase: 57.7 in

Ground Clearance: 14.8 in

Wet Weight: 224.8 lb

Fuel Capacity: 1.7 gal

Warranty: 30 Day (Limited Factory Warranty)

For discussion on the Yamaha YZ250F or on Yamaha Motorcycles clink on link.

Premix – Smells like victory

Born from the award winning YZ competition bikes, the 2010 Yamaha YZ125 features a light aluminum frame with a powerful, compact engine with awesome power-to-weight ratio. The 2010 YZ125 is ready to race out of the crate complete with ProTaper aluminum handlebar, titanium footpegs and gripper seat.

While some manufacturers are putting all their eggs in one basket, the engineers at Yamaha believe that choice is a good thing.

So whether your weapon of choice is a berm blasting two stroke or arm stretching four stroke, we have your needs covered.

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.

Engine

•  Reed-valve spacer improves acceleration across the entire powerband.

•  Amazingly compact 124cc reed-valve-inducted two-stroke helps produce an awesome power-to-weight ratio.

•  Patented YPVS® power-valve system combines crisp, hard-hitting bottom-end acceleration with strong midrange and eye-opening top-end.

•  38mm Mikuni® TMX carburetor gives excellent throttle response and serious horsepower.

•  Six-speed, close-ratio transmission optimizes gear ratios for maximum performance.

•  Digital CDI ignition system delivers precise spark and monitors engine speed to ensure optimal timing for faster, stronger response during hard acceleration.

•  Large-capacity radiator features a 10-row core with four louvers to deliver maximum cooling efficiency at all performance levels.

•  Primary kickstarting ensures easy restarts in any gear.

•  Trick, works-style clutch lever features race-spec barrel adjuster for on-the-fly adjustability.

Chassis/Suspension

•  YZ250F-style front-brake caliper and wave-style front and rear discs minimize unsprung weight and provide excellent stopping power.

•  A carefully engineered, advanced aluminum frame and swingarm give the YZ125 the best handling in its class.

•  Speed-Sensitive System 48mm KYB® fork; damping force is controlled by piston speed which provides a smoother, more precise ride.

•  Removable aluminum rear subframe is 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 all add up to fantastic rear wheel control and a sweet ride.

•  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

•  Special-design “gripper” type seat and fuel tank, forward-canted steering crown and low ProTaper® handlebar all help create greater freedom of movement and more comfortable ergonomics for riders.

•  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.

•  Premium drive chain has gold-colored plates for outstanding looks.

•  Wide-diameter fuel tank cap for easier refueling.

•  Repackable exhaust silencer.

•  Durable, comfortable handlebar grips.

2010 Yamaha YZ125 – USA Specifications
MSRP* $6,090 (Team Yamaha Blue/White) Available from February 2010

Engine

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

Chassis

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

Dimensions

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)

For discussion on the Yamaha YZ125 or on Yamaha Motorcycles clink on link.

Born from the award winning YZ competition bikes. The 2010 YZ85 features a liquid-cooled, 84.7cc crankcase reed-valve-inducted six-speed that is compact and light. You also get an ultra-rigid, single backbone, semi-double-cradle frame, fully adjustable suspension and more to suit a wide range of rider from novice to mini expert.

With the same chassis and engine technology that goes into every 2-stroke YZ, the scaled-down YZ85 is a true competitor.

The YZ85, with its ultra-rigid high-tensile steel frame and 36mm inverted forks, weighs just 55kg (126lbs.) Powered by a compact yet muscular liquid-cooled 85cc engine pumping the power through a six-speed gearbox, this bike’s engineered to catch some major air — and trophies, too. Fully adjustable suspensions, front and rear disc brakes and almost 11″ of wheel travel highlight “for competition use only.” Truly, this is full-sized performance in a scaled-down package.

Key Features

• Liquid-cooled, 84.7cc crankcase reed-valve-inducted six-speed is light, compact and designed to deliver hard-hitting, moto-winning power throughout the rpm range.

• 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; seamless throttle response across the powerband is the result.

• 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 for outstanding acceleration and corner-exiting power.

• 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/Suspension

• 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 for optimal suspension performance.

• 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.

2010 Yamaha YZ85 – USA Specifications
MSRP* $3,690 (Team Yamaha Blue/White) Available from February 2010

Engine

Type: 84.7cc liquid-cooled 2-stroke; reed-valve inducted

Bore x Stroke: 47.5 x 47.8mm

Compression Ratio: 8.2:1

Fuel Delivery: Keihin® PWK 28

Ignition: CDI

Transmission: Constant-mesh 6-speed; multiplate wet clutch

Final Drive: Chain Drive

Chassis

Suspension/Front: Inverted fork; fully adjustable, 10.8-in travel

Suspension/Rear: Single shock; fully adjustable, 11.1-in travel

Brakes/Front: Hydraulic single disc brake, 220mm

Brakes/Rear: Hydraulic single disc brake, 190mm

Tires/Front: 70/100-17-40M

Tires/Rear: 90/100-14-49M

Dimensions

Length: 71.7 in

Width: 30.9 in

Height: 45.7 in

Seat Height: 34.0 in

Wheelbase: 49.5 in

Ground Clearance: 13.8 in

Fuel Capacity: 1.3 gal

Wet Weight: 156 lb

Warranty: 30 Day (Limited Factory Warranty)

For discussion on the Yamaha YZ85 or on Yamaha Motorcycles clink on link.

New bikes amke some people stare. The revolutionary new 2010 YZ450F will have many gazing far into the future.

But slanting the cylinder rearward and reversing the intake and exhaust ports, the 2010 Yamaha YZ450F’s mass is more centralized for amazing balance, unprecedented handling and cornering. The all-new Bilateral Beam frame and suspension offer fantastic feedback to the rider. Add fuel injection to the mix of of these new innovations and you’ll agree: backward is the right way forward.

Fuel injection, “reversed” rearward slanted engine, Tornado exhaust, “Bilateral Beam” frame, new swingarm, longer suspension travel … the list of improvements goes on.

The new YZ450F features engine and chassis designs that separate Yamaha from the competition. The YZ450F is a “no compromise” machine designed to win with styling highlights that will turn heads at the same time.

Highlights:

New rearward slanting “reversed” engine

New Bilateral Beam frame

All New for 2010

” YZ450F’s new rearward-slanted cylinder is a revolutionary advancement that achieves unmatched mass centralization, concentrating inertial mass toward the center of the machine. This bold new design also swaps traditional intake and exhaust positions, putting the lightweight airbox and throttle body out front. This contributes to mass centralization for nimble handling while also achieving a straight intake tract for superb combustion efficiency that delivers more power.

” The cylinder is offset so the connecting rod is vertical at the moment of greatest combustion force, minimizing piston friction against the cylinder wall that could rob power. That means quicker response.

” The new 4-titanium valve cylinder head is matched to a fuel injection system developed specifically for the YZ450F. Instantly adapts to changing air/fuel mixtures depending on altitude and temperature, for an engine that delivers no matter what conditions.

” The all-new aluminum Bilateral Beam frame provides a superb rigidity balance that complements the engine for unmatched lightweight handling and cornering. The result? The best cornering, most nimble 450F for all track conditions.

” Revamped looks deliver new-generation styling, including front and rear fenders, intake cover, front fork protector, and number plate, along with the fuel tank and seat.

” Accessory GYTR® Power Tuner lets bike tuners adjust air/fuel mixture and ignition timing maps to match engine performance characteristics to the rider and track conditions.

Features andBenefits (USA):

Key Features:

Engine:

” The rearward-slanted engine allowed engineers to design straight intake and exhaust ports, creating the most direct path for air flow into the fuel-injected engine for incredible performance.

” The YZ450F uses a battery-less fuel injection system with a 12-hole injector for superb fuel atomization. The 44mm Keihin® throttle body is designed for easy starting, with an integrated cold start and idle speed adjustment knob. Yamaha FI provides optimal air/fuel mixtures in all altitudes and wide range of temperatures for outstanding throttle response.

” 14 volt / 110W high output generator powers the battery less fuel injection system.

” 4-titanium valve cylinder head with a “pent-roof” design combustion chamber provides excellent combustion efficiency and unequalled power output.

” Intake and exhaust camshaft profile changes to increase valve working angle and valve lift for most excellent performance at all rpm.

” The bigger 97.0mm bore and shorter 60.8mm stroke, along with a higher 12.5:1 compression ratio, create a combustion chamber that delivers really impressive power.

” The air filter case is changed to accommodate the new engine layout. Putting it up front keeps dirt and dust kicked up from the rear tire away from the intake system.

” New “tornado-style” exhaust header with resonator efficiently scavenges exhaust gasses and helps the engine achieve its exceptional low-to-mid range torque characteristics, while the 150mm-longer muffler comfortably meets the latest noise standards without a sacrifice of power.

” Clutch and transmission components have been thoughtfully revamped to give the rider great shifting feel.

Chassis/Suspension:

” The aluminum Bilateral Beam frame is crafted from a carefully chosen combination of forged and extruded aluminum, 16 components in all, for the right rigidity balance and light weight. A very symmetrical chassis design promotes nimble handling, letting riders enter and exit corners as quickly as possible to put the competition behind them.

” New skid plate is constructed from tough polypropylene for great protection and low weight.

” The swingarm and rear shock are redesigned, with the shock mounted along the central axis of the frame, taking advantage of the space no longer needed for the front-mounted airbox. This optimized combination delivers exceptionally linear performance for excellent bump absorption and awesome cornering ability.

” The KYB® Speed Sensitive front fork has 10mm longer stroke for excellent feel and shock absorption.

” KYB® rear shock with large capacity piggy back reservoir and 50mm piston for more consistent damping control.

” New fuel tank is positioned underneath the seat, contributing to the centralized mass. The seat is long and flat for to allow free rider movement.

” New rear sprocket shape has a trick appearance and is light weight.

” The triple clamps are redesigned, with a change in offset from 25 to 22 mm for unequalled cornering performance. The ProTaper® bars are four-way adjustable to accommodate a wide range of riders.

” The front and rear fenders, along with the number plate, side cover and front fork protector have been redesigned for an aggressive look. Less plastic is used to expose and enhance the lightweight aluminum frame.

Additional Features:

” Fuel pump is small and lightweight, as is the compact transistor ignition unit.

Features and Benefits (Canada)

Engine:

” All new, “reversed” liquid-cooled, 450cc, DOHC, 4-valve, 4-stroke, single with fuel injection and titanium valves. The engine has been tuned for excellent “drivability and controllability” one of the most important keys to fast lap times. The engine delivers a broad power curve with a great over-rev capacity.

” This all new, unique engine design features a rearward slanting cylinder that is “reversed” compared to traditional designs. The FI throttle body and air box are front mounted while the exhaust exits from the rear of the cylinder. This design is used to centralize mass for excellent handling and a light feel. The other major benefit is the straight shot intake system which maximizes power output. The engine is slanted 7.5 degrees rearward.

” The “reversed” design allows for a straight intake path into the cylinder, providing maximum intake flow and efficiency for excellent power. The front positioned intake means that engine heat will have less “heating effect” on the incoming fuel charge (cooler fuel helps increase power).

” Centrally located spark plug and the new design of the 4-valve head promotes a “tumbling effect” of the inbound fuel / air for better combustion, improved throttle response and power output.

” All new, compact, 4-valve cylinder head design, features a 12.5:1 compression ratio (Vs 12.3 for ‘09). The intake valves are 36mm in diameter and the exhaust valves are 30mm.

” Lightweight titanium valves (intake & exhaust) and new load-reduced oval valve springs reduce reciprocating mass for less friction, faster-revving and smoother-hitting power delivery across the rev range.

” The bore has been increased by 2mm while the stroke has been shortened by 2.6mm compared to last year’s model.

” Automatic cam chain tensioner reduces maintenance and new cam chain “sliders” reduce internal frictional losses.

” All new, hollow design intake and exhaust camshafts feature new valve timing and lift specifications for improved power.

” The lightweight aluminium cylinder features a ceramic composite coating which is applied directly to the aluminium, eliminating the need for a heavy iron sleeve or liner. The ceramic coating insures faster, more uniform heat dissipation, reduced friction and a longer service life.

” The cylinder is “offset” relative to the crankshaft to reduce frictional losses between the piston and the cylinder wall during the power stroke. This offset design is a first on a Yamaha motocross machine.

” New, more rigid crankcase to accommodate the increased engine power

” New design crankcase utilizes an integrated oil tank inside the cases to supply oil to the dry sump lubrication system. This design concentrates mass lower in the frame for optimum handling and lighter weight feeling. There are no exterior oil lines with this design and the internal oil tank is designed to promote air – oil separation.

” Special cylinder design features cutaways that allow the air “trapped” under the piston to enter a side chamber (or cutaway) to reduce horsepower-robbing “pumping losses.”

” The crankcase also utilizes cutaways to reduce “pumping losses”. The crankcase cutaways match the cutaways in the cylinder for maximum efficiency.

” All new short-skirt, forged piston provides excellent reliability, less mechanical vibration and reduced weight.

” Newly designed piston rings reduce friction for improved power and reduced oil consumption.

” Piston oil cooler utilizes a pinpoint nozzle that directs oil to the desired portion of the cylinder and underside of the piston, which reduces piston, cylinder and rod temperatures for great durability.

” Oil volume in the engine has been optimized to reduce weight and oil drag related power losses.

” Revised, lightweight gear driven balancer shaft reduces vibration for improved rider comfort and less rider fatigue.

” The crankcase features a tri-axis layout for the crank, main and drive axles. This tri-axis design keeps the crankcase more compact while also centralizing mass for excellent handling. All of the shafts are positioned low in the cases to maintain a low centre of gravity.

” Revised multi-plate wet clutch features a new clutch push lever assembly and revised push rod. The benefit is improved clutch feel and reduced clutch lever effort.

” Revised, 5-speed transmission features “involute splines” on the transmission axles to ensure smooth shifting and instant hook-up under power. There are numerous changes to the transmission including engagement dog shape, shift cam “pattern” and revised shift forks. The benefit is smooth, positive shifting

” 5-speed transmission optimizes engine performance. This 5-speed transmission provides great performance and makes the YZ450F very versatile for MX, Hare Scrambles, Super Moto, Ice Racing and Enduro type applications.

” Quick-access, lightweight magnesium outer clutch cover for fast, easy clutch maintenance.

” All new Keihin 44mm throttle body fuel injection system is a battery-less design for reduced weight and is designed specifically for MX applications. The 12-hole injector maximizes fuel atomization for more complete combustion and great power output. The benefits of fuel injection include constant ongoing adjustments to insure the optimum fuel – air ratio regardless of outside air temperature and altitude. Other benefits include improved starting and improved throttle response. The system is equipped a throttle position sensor (TPS), plus a range of sensors (engine temp, outside air temp and air pressure etc.). There is also a cold start and fast idle knob which doubles as an idle adjuster too.

” The injector spray pattern, spray direction and the distance to the intake valves have been optimized, while the specially designed straight intake tract helps to maximize the benefits of the FI system and overall power output.

” Optional, compact, hand held “YZ Power Tuner” allows tailoring of both fuel injection settings and ignition mapping. Nine (9) different setting points can be accessed for both the FI and ignition maps. Maps can be stored and shared with other Power Tuners if desired. The days of removing a carb to make jetting changes are gone.

” New, compact, lightweight in-tank electric fuel pump

” A new larger capacity ACM (alternating current magneto) is used to eliminate the need for a battery.

” Automatic decompression system ensures easy starts in any gear with no manual lever to fuss with.

” All new air box (located behind the steering head) features a straight shot intake boot and a new washable, dual-stage, foam air filter.

” All new “Tornado” design exhaust system exits from the “rear” of the cylinder. The spiral winding of the header pipe provides the correct “tuned” length and takes full advantage of the exhaust “pulse” effect to maximize cylinder filling. There is a “resonator” (or power chamber) built into the header pipe. Another benefit of this new exhaust system is mass centralization

” New re-packable lightweight aluminium / stainless steel muffler has been designed to optimize the performance of the new engine. This muffler complies with both CMRC and AMA 2010 noise limits.

” Revised compact, lightweight, single core, dual radiators provide outstanding cooling efficiency.

” All new ECU controls the ignition and fuel injection processes. There is also a “G” sensor system that will shut down the fuel injection system if the bike lies on its side for more than 10 seconds. There is no special procedure to re-start the bike … just kick it and go. The ignition timing maps are all new to maximize the benefit of both the FI system and the new engine characteristics.

” Works-style race-spec “barrel adjuster” for on-the-fly clutch adjustability.

” Easy access oil filter.

Chassis/Suspension

” All new, compact “bilateral beam” aluminium frame centralizes mass for exceptional handling. This 450cc class specifically designed frame consists of a “High Solid Die Cast” head pipe, hydro formed main rails plus various forged and extruded components. This all new frame is compact and offers significantly improved “rider – machine communication” (a.k.a. feedback). The engineers have optimized the balance between strength, rigidity and flex. The key goal of this new chassis is faster and easier cornering … one of the keys to winning races. The engineers started with a clean sheet of paper and designed the chassis based on the requirements of a 450cc motocrosser. Note: the YZ450F frame is unique unto itself.

” The rigidity balance of this new frame has been optimized and features high lateral and torsional rigidity with “tuned flex” in the longitudinal direction. The result is a feeling of lightness, agility and traction.

” New, lightweight, tapered, aluminium swingarm is produced using “hydro forming”, a special method that uses high pressure liquid to form shapes. The shock is now positioned in-line with the central axis of the bike and there are new linkage mounting locations on the swingram. The rear axle pinching area is thicker and stronger, while the swingarm pivot shaft is now 17mm.

” Lightweight removable rear sub frame is constructed of square-section, lightweight aluminium pipe. The detachable design allows easy access when servicing rear suspension components.

” New cast aluminium upper and forged aluminium lower triple clamps are revised and reduce the fork off set (from 25mm to 22mm) and offer great rigidity and strength.

” As in 2009, there are a total of 4 different handlebar positions available (thanks partly to the offset design of the aluminium handlebar clamps) with an adjustment range of 30mm, to suit a wide variety of riders.

” Pro Taper bars provide excellent strength and durability. Foam handlebar pad is included.

” Revised 48mm, adjustable, inverted, Kayaba cartridge forks offer an additional 10mm of travel for 2010. These forks feature a twin-chamber design which means the damper unit is in a separate structure which prevents aerated fork oil from entering the inner damper assembly and reducing its damping abilities. Since the inner damper is pressurized, it also eliminates bubbles forming in the oil. Front fork adjustments include: 20-way compression damping and 20-way rebound damping. Optional fork springs are available through Genuine Yamaha parts.

” The balance between the inner and outer tubes is 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.

” The 48mm inverted KYB fork also features a Transfer Control Valve (TCV). The TCV enhances the damping force from mid to full stroke and improves bottoming characteristics. The benefit of TCV is more precise control throughout the full suspension stroke. The 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 fork”.

” “Kashima coating” has been applied to the fork tubes to reduce friction for smoother suspension performance. Front wheel travel is 310mm (12.2″).

” Revised, large “wrap-around” plastic fork protectors provide excellent lower fork tube protection. The “self-supporting” design reduces friction for smoother fork operation.

” New Monocross link rear suspension system features a revised fully adjustable Kayaba, piggyback shock which provides 315mm (12.4″) of wheel travel and features separate adjusters for high- and low-speed compression damping. The shock is now in-line with the center axis of the bike for excellent control. Adjustments include: spring preload, 20-way rebound damping, 20-way low-speed compression damping and 2 turns of high speed compression damping.

” The revised shock uses an 18mm diameter piston rod. 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. The shock spring location is 30mm lower than last year, reducing the centre of gravity.

” 250mm floating front wave-style disc reduces weight, improves cooling and adds style too. The disc is squeezed by a Nissin twin piston caliper fitted with lightweight aluminium pistons.

” “Shorty style” adjustable front brake lever.

” 245mm rear disc brake features a “wave-type” disc. The rear disc is squeezed by a single Nissin piston caliper.

” Lightweight, compact, integrated Nissin rear master cylinder (fluid reservoir is integrated into the top of the master cylinder) provides strong stopping power with excellent feel and control.

” The rear caliper and the lower portion of the wave disc are protected by heavy duty plastic protectors.

” Newly designed, compact body work includes front number plate, front fender, rad shrouds, fuel tank, side panels and rear fender which enhance the lightweight feel and look of the new YZ450F. This new “minimal” bodywork is a flat design, allowing for fast, easy rider movements. The ergonomics provide a natural and roomy riding position. The body has been designed to maintain it good looks throughout the life of the machine.

” The lightweight, plastic resin 6 litre fuel tank is located under the seat, once again reducing the centre of gravity and centralizes mass for exceptional handling performance.

” New lightweight Sun Star rear sprocket.

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

” Large 25mm rear axle and a hub design which features a second bearing on the sprocket side for increased rigidity.

Details

” New polypropylene engine and water pump guards reduce weight.

” Lightweight, extra wide foot pegs provide excellent grip and ground clearance.

” Folding shift lever tip helps prevent damage.

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

” Lightweight chain guide / support helps reduce chance of chain derailment. Also helps protect rear sprocket damage too.

” Heavy duty rubber swingarm protector

” Heavy duty DID 520 drive chain

” Convenient oil level sight glass

2010 Yamaha YZ450F – USA Specifications
MSRP* $8,090 (White/Red) Available from September 2009
$7,990 (Team Yamaha Blue/White) Available from September 2009

Engine
Type 449cc liquid-cooled DOHC 4-stroke; 4 titanium valves

Bore x Stroke 97.0 x 60.8mm

Compression Ratio 12.5:1

Fuel Delivery Yamaha Fuel Injection (YFI), Keihin® 44mm

Ignition CDI

Transmission Constant-mesh 5-speed; multiplate wet clutch

Final Drive Chain Drive

Chassis
Suspension/Front KYB® Speed-Sensitive System, inverted fork: fully adjustable, 12.2-in travel

Suspension/Rear KYB® 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-Dunlop® D-742FA

Tires/Rear 120/80-19-Dunlop® D-756

Dimensions
Length 86.3 in

Width 32.4 in

Height 51.6 in

Seat Height 39.3 in

Wheelbase 58.7 in

Ground Clearance 15.0 in

Fuel Capacity 1.6 gal

Wet Weight 245 lb

Other
Warranty 30 Day (Limited Factory Warranty)