In 2010, Yamaha plans to rule all competitions involving 450cc dirt bikes with their entirely redesigned YZ450F model. This is a bike that with ingenious engineering solves a big problem for all bikes in its category – space. It features a reversed cylinder engine allowing the entire reorganization of the engine bay and it is all mounted on a completely new, lighter frame. The rest is just a matter of finesse and it is all covered in the following article.
The much anticipated reverse-cylinder 2010 Yamaha YZ450F motocross model is a revolutionary new machine with plenty to prove in its field, especially when professional motocross and supercross riders get their hands on it. To begin with, this is the only 2010 dirt bike to feature a reversed cylinder, a construction method that centralizes inertial mass and strengthens the intake track in order for the engine to develop more power and the bike to handle sweeter overall. Also, better throttle response is achieved because the cylinder is offset, meaning that the connecting rod is vertical when everything goes bang in the cylinder. This also reduces the friction between the piston and the cylinder.
The entirely new bike now comes with a smaller, 1.6-gallon tank, which is now located under the seat, lowering the bike’s center of gravity. Also, the airbox is now mounted up front and the shock is found along the frame’s central axis.
While the engine arrangement itself is a revolutionary engineering method, the bore x stroke is now 97.0mm x 60.8mm and the cylinder head features four titanium valves. Fuel is brought in by a 12-hole fuel injector and 44mm Keihin throttle body powered by a battery-less 14-volt/110w generator. Thanks to these features, the air/fuel mixture should be ideal at all temperatures and altitudes. In fact, this bike should be the ultimate 450cc motocrosser in 2010 as it even has an optional GYTR Power Tuner plug-in fuel-injection setting device that makes it easy to adjust fuel mixture load and ignition maps so you can custom tune the YZ450F performance depending on your preferences, riding conditions or after you have added an aftermarket air filter or exhaust.
The YZ450’s Bilateral Beam Frame is built from 16 aluminum components. Like most frames, it’s designed to take your weight and height into consideration when it comes to rigidity. But taking it to the next level, this new design also considers riding position and rider movements and inputs into the chassis to provide an ideal level of rigidity balance.
The new frame works closely together with the bike’s new suspension, a new 48mm speed-sensitive Kayaba front fork has even more damping control with 10mm longer stroke. This promotes an even smoother ride with better bottoming resistance, better traction and feel with smooth damping and supple response under the most demanding riding conditions.
At the back, a 50mm Kayaba rear shock has an even higher capacity piggy back reservoir. The YZ450F’s new rear shock is claimed to offer more control over the bike’s rear as well as more damping under harsh riding.
As you can clearly see, Yamaha concentrated on pure engine and chassis performance when designing the new YZ450F and it is all made possible with the proper exploitation of space, especially in the engine bay. This translates into better mass centralization, which should make the thing feel lighter, but we’ll have to see that when getting on the actual bike.
The 2010 Yamaha YZ450F is the kind of motorcycle that sends the competition back to the drawing board. So while the 2010 Honda CRF450R , 2010 Kawasaki KX450F and 2010 Suzuki RM-Z450 might currently seem dated in comparison to Yamaha’s ingenious piece of engineering, we’re expecting tough responses from the three Japanese manufacturers that have reunited their engineers with the good old pencil and a clean sheet of paper.
But European manufacturers such as KTM and Husqvarna have also taken the news pretty bad and need to start from scratch with their 450cc motocross bikes, the 450 SX-F , respectively the TC 450 .
With the launch of the all-new 2010 YZ450F dirt bike, Yamaha has definitely set itself as the class leader, at least in what concerns one’s ability to show the direction in which this industry’s heading and a trained eye will spot that from the very first glance. The thing with dirt bikes is that they don’t need excellent aerodynamics, but they do have to be compact and extremely well balanced from obvious reasons. And this is precisely what Yamaha followed with this new model on which every single piece, be it mechanical or bodywork, is part of a whole new game of looking aggressive.
First thing first, the engine is inclined towards the back rather than the front, like we were all used to, and this changes the position of the gas tank and that of the airbox. These pieces have virtually switched places, meaning that the 1.6 gallons fuel tank is now positioned underneath the redesigned seat. The thing is actually made from a translucid material so that you can see how much gas it has inside, which is cool.
The body panels are brand new and because they now don’t need to hug a fat gas tank look slimmer, more aggressive, but also more refined. They blend in with the tank, seat and, through this middle piece, with the rear fender and number plates, defining the new look of the modern motocross bike. Up front you get pretty much the same aggressive fender and number plate. This Yamaha dirt bike rolls down the track on Excel wheels and features Team Yamaha Blue/White and White/Red as the only color schemes available.
"The 2010 YZ450F has a new heartbeat. This motor must make more power than last year’s and it surely delivers it with more ferocity. We have a ton of traction here at Budds Creek, so the bike isn’t breaking loose, but it feels like it could if we found a gap in the grip." – dirtrider
"Out on track the first thing one observes is just how peppy the new engine is. Budds has numerous steep climbs that really load the engine and expose any shortcoming. We came away really impressed by not only how powerful the engine is but how easy that power is to use." – motorcycle-usa
"While there’s nothing really wrong with the YZ’s engine performance, it hits pretty hard right off the bottom. The map we settled on simply knocks the edge off that hit." – motorcyclistonline
“…the bike feels very light and corners very well. That’s the main point of having the new engine configuration. By keeping the heaviest parts of the bike near the center, it should make the entire package more maneuverable. The theory seems to have merit.” – dirtbikemagazine
“It’s the most nimble handling 450 ever,” said Tim Olson, media relations manager for Yamaha’s off-road division, which Joey corroborated. “(Its handling is) Suzuki-like, without sacrificing any of its good ‘ol stability.” Joey added that the mass-centralization efforts made the YZ “feel very light out on the track and gave me the ability to direct the bike where ever I wanted.” – motorcycle
"Yes, it appears the revolutionary Yamaha YZ450F lives up to all of the hype, just like it did 12 years ago when Yamaha debuted the revolutionary YZ400F. We can’t imagine what they’ll come up with next, 12 years from now." – cyclenews
The 2010 Yamaha YZ450F starts at $7,990 if the classic racy blue/white is your color of choice and at $8,090 if 2010’s special color blinks an eye at you.
This year, motorcycle companies were mostly retained in launching radical new motorcycles and this is partly why Yamaha gets all the vaunts. Still, we don’t see any other maker launching a similar model sooner than 2011, so expect the 2010 YZ450F to rule motocross and supercross competitions with its reversed cylinder and brand new chassis.
Engine and Transmission
- 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 and Dimensions
- 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
- 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
- Warranty: 30 Day (Limited Factory Warranty)
Features & Benefits
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.
- 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.
- 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.
- Fuel pump is small and lightweight, as is the compact transistor ignition unit.