2012 Yamaha YZ450F DirtBike

2012 Yamaha YZ450F Review

Stop staring, take it to the line...

The revolutionary YZ450F: So forward thinking everything else seems backwards.

Lighter and even more responsive, the new 2012 Yamaha YZ450F delivers unprecedented confidence off the start gate, in the corners and over jumps.

There's nothing like sitting on the starting line, knowing that you'll be to the first corner first.

The new YZ450F begs to be admired by racers and mechanics alike. It's backward, rearward slanted cylinder and "tornado" exhaust design is mechanical genius—and it's exclusive to Yamaha's YZ450F! By moving more weight to the centre of the bike, it lightens up the front end for quicker turning and excellent balance. In fact, on the track, the 450F feels like a 250F—until you snap the throttle! If you thought the '11 YZ450F was snappy, wait until you ride the '12; fuel injection settings have been updated for even faster response. Weight has been shaved as well by using new materials in the front and rear suspension. Confidence is king in racing. Get it with the YZ450F.

Other bikes, please move to the rear.

The revolutionary 2012 Yamaha YZ450F will have many gazing far into the future. By slanting the cylinder rearward and reversing the intake and exhaust ports, the 2012 YZ450F's mass is more centralized for amazing balance, unprecedented handling and cornering. The Bilateral Beam frame and suspension offer fantastic feedback to the rider. Add fuel injection to the mix of these innovations and you'll agree: backward is the right way forward.

2012 Yamaha YZ450F Highlights and Key Features:

Updated Fuel Injection settings

Lighter Weight

GYTR Power Tuner: customizable power delivery

Key Features:

•YZ450F's still revolutionary design advancements include its rearward-slanted cylinder that achieves unmatched mass centralization, concentrating inertial mass toward the center of the machine. This bold design 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 4-titanium valve cylinder head is matched to a newly recalibrated fuel injection system that provides superb low-to-mid-rpm power feeling. Instantly adapts to changing air/fuel mixtures depending on altitude and temperature, for an engine that delivers no matter what conditions.

•The aluminum double "S" bend Bilateral Beam frame provides a superb rigidity balance and, with new front and rear suspension settings, provides unmatched lightweight handling and cornering. Combined with the mass centralization provided by the engine, YZ450F for 2012 is a formidable, well-tuned package.

•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.

New for 2012:

•Revised fuel injection settings (mapping for injection and advance) offer smooth, controllable engine response in the low-to-mid-rpm range.

•New, longer 94 dB muffler.

•ECU programming is updated to optimize performance characteristics with the new-spec muffler.

•New front and rear suspension settings and valving deliver exceptionally smooth suspension performance.

•Dunlop® Geomax® MX51 tires provide great all-round traction.

•New seat foam material has an excellent cushion feel.

•Both color options feature rich-looking black rims and a gold-color drive chain.

2012 Yamaha YZ450F Features and Benefits

ENGINE

"Reversed" liquid-cooled, 450cc, DOHC, 4-valve (titanium), 4-stroke, single with fuel injection. The engine has been tuned for excellent "drivability and controllability" one of the keys to fast lap times. The engine delivers a broad power curve with a great over-rev capacity.

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 4-valve head promotes a "tumbling effect" of the inbound fuel / air for better combustion, improved throttle response and power output.

Compact, 4-valve cylinder head design, features a 12.5:1 compression ratio. The intake valves are 36mm in diameter and the exhaust valves are 30mm.

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

Automatic cam chain tensioner reduces maintenance while special cam chain "sliders" reduce internal frictional losses.

High performance, light weight hollow intake and exhaust camshafts.

The lightweight aluminum cylinder features a ceramic composite coating applied directly to the aluminum, 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.

Crankcase design 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 or tank with this design.

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.

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

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.

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 5-speed transmission features "involute splines" on the transmission axles to ensure smooth shifting and instant hook-up under power. The shift cam and shifter forks have been revised for more precise shifting and improved feel.

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.

Keihin 44mm throttle body fuel injection system is a battery-less design for reduced weight and is designed specifically for off road 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.

Compact, lightweight in-tank electric fuel pump

High capacity ACM (alternating current magneto) is used to eliminate the need for a battery.

Automatic decompression system ensures easy starts in any gear.

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

"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 key benefit of this exhaust system is mass centralization

Revised re-packable lightweight aluminum / stainless steel muffler (aka silencer) is 42mm longer than in 2011 with a longer internal exit spigot. The sound output is 94dba to meet the current AMA noise regulation. Muffler disassembly is easy since the silencer bolts together with Allen screws.

Compact, lightweight, single core, dual radiators provide outstanding cooling efficiency

Revised high powered ECU controls the fuel injection mapping and ignition timing mapping. The ECU has been re-mapped for improved low and mid range performance.

Special "G" sensor system will shut down the fuel injection system if the bike lies on its side for more than 10 seconds to help prevent costly engine damage. There is no special procedure to re-start the bike … just kick it and go.

Works-style race-spec "barrel adjuster" for on-the-fly clutch lever free play adjustments.

Easy access oil filter.

CHASSIS / SUSPENSION

Compact "bilateral beam" aluminum 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 frame is compact and offers excellent "rider - machine communication" (a.k.a. feedback). The engineers have optimized the balance between strength, rigidity and flex. The key goal of the chassis is faster and easier cornering … one of the main 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, it is not the same as the YZ250F frame.

The rigidity balance of the 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 excellent traction.

Lightweight, tapered, aluminum swingarm is produced using "hydro forming", a special method that uses high pressure liquid to form shapes. The swingarm pivot shaft is 17mm.

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

Cast aluminum upper and forged aluminum lower triple clamps. Fork off set is 22mm.

Adjustable handlebar clamps offer a total of 4 different handlebar positions with an adjustment range of 30mm, to suit a wide variety of riders.

ProTaper handlebar provides excellent strength and durability. Foam handlebar pad is included.

Revised, 48mm, adjustable, inverted, Kayaba cartridge fork with 310mm (12.2") of wheel travel. Front forks have been re-valved to increase low-to-mid compression damping. The fork is also lighter due to an internal weight reduction of the cylinder head and tank (these are fork internals … not engine internals).

The fork features a twin-chamber, "Speed Sensitive" design meaning 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 fork tubes is optimized, while the Kashima coating on the pressure tank and the piston rod reduces friction for smoother suspension performance.

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".

Large "wrap-around" plastic fork protectors provide excellent lower fork tube protection. The "self-supporting" design reduces friction for smoother fork operation.

Monocross link rear suspension system features a revised, fully adjustable, large capacity, 50mm Kayaba piggyback shock which provides 315mm (12.4") of wheel travel and features separate adjusters for high- and low-speed compression damping. The revised shock features a valving change on the rebound side for improved performance with less bottoming, a new rebound adjuster oil passage and improved valving with less low-speed rebound and more high-speed compression. The shock is in-line with the center axis of the bike for excellent control. Shock adjustments include: spring preload, 30-way rebound damping, 20-way low-speed compression damping and 2 turns of high speed compression damping.

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.

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

"Shorty style" adjustable front brake lever can be adjusted to fit various hand sizes.

245mm rear disc brake features a "wave-type" disc. The rear disc is squeezed by a single compact 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.

Compact body work enhances the lightweight feel and look of the YZ450F. This "minimal design" 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.

Lightweight, plastic resin 6.2 litre fuel tank is located mostly under the seat, once again reducing the centre of gravity and centralizing mass for exceptional handling performance.

Lightweight Sun Star rear sprocket.

Rugged, 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 and durability.

Revised seat material reduces weight and improves rider comfort. The "pebble" seat surface texture has been designed to give a grip when needed, yet still allow easy rider movements. The seat cover resists clogging with dirt or mud to ensure long lasting good looks.

E10 friendly fuel system components

New Dunlop Geomax MX51 Tires.

ADDITIONAL DETAILS / FEATURES

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.

Adjustable clutch lever can be adjusted to fit various hand sizes.

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

Lightweight chain guide / support helps reduce chance of chain derailment and also helps protect the rear sprocket.

Heavy duty rubber swingarm protector

Heavy duty gold coloured DID 520 drive chain

Convenient oil level sight glass

E10 friendly fuel system components

2012 Yamaha YZ450F - Specifications/Technical Details

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 TCI
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® Geomax® MX51
Tires / Rear 120/80-19 Dunlop® Geomax® MX51

DIMENSIONS
Length 86.4 in
Width 32.5 in
Height 51.6 in
Seat Height 39.4 in
Wheelbase 58.7 in
Ground Clearance 15.2 in
Fuel Capacity 1.6 gal
Wet Weight*** 245 lb