Yamaha YZ450F Bikes
Yamaha’s largest and most powerful dirt bike is the YZ450F, which has evolved from what used to be the YZ400F, and then a slightly larger YZ426F. The YZ400F was introduced in 1998, and was the first four-stroke motorcycle that was directly competing with two-strokes. It immediately caught everyone’s attention with an AMA National Motocross Championship won by Doug Henry, the first on a four-stroke machine.
Yamaha took the YZ400F and began updating it in 2000, adding 26cc to increase power and throttle response, and updating the carburetor and jets in order to make start up easier. More titanium was used starting in 2001, making the bike lighter, faster, and easier to maneuver. The suspension also had a few modifications in order to decrease weight and a smoother ride.
In 2003, the YZ450F was finally introduced, and would revolutionize the mx racing world. This was the first time that 450cc bikes were allowed in AMA Motocross races, and Yamaha was all about being the leader. In the engineering process, Yamaha was able to shed about 17 pounds from their YZ426F, and changed the YZ from a five-speed transmission to a four-speed. Many riders thought that this bike had too much power for an mx track, so in 2006, an all new YZ450F was released that was once again a five-speed transmission, wasn’t "too" powerful, and was much easier to ride.
2008 brought much success to the YZ450F, allowing James Stewart to capture the AMA Motocross Championship, and Chad Reed to win the AMA Supercross Championship.
For 2010, Yamaha has revolutionized the YZ450F, yet again. Yamaha has figured out ways to further centralize the mass of the bike, as well as make it more powerful. The cylinder is now slanted toward the rear, causing the inertial mass to be centralized. This new design also switches the intake and exhaust positions, straightening the intake tract for a more efficient combustion, equaling more power. The cylinder is now also offset, which causes the connecting rod to be vertical at the point of greatest force, minimizing piston friction, increasing response time.
The new YZ450F also has a new 4-titanium valve cylinder head that has been matched to a new fuel injection system. The new system adapts to air/fuel mixtures as soon as they change, ensuring that the engine is always running properly, no matter the conditions. A GYT-R Power Tuner is also available, allowing you to tune the mixture and ignition timing maps manually, according to your track conditions.
A new aluminum Bilateral Beam frame makes for excellent balance, handling, and cornering on any track. The front fork protector, front and rear fenders, intake cover, fuel tank, seat, and even the number plate have been re-designed, giving the 2010 Yamaha YZ450F a killer new-generation style, all of its own.