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Yamaha Dirt BikesAfter the Second World War, then company President Gen-ichi Kawakami decided to make use of a production line and tooling that had previously been used to produce aircraft propellors to produce what was the forerunner of the Yamaha dirt bikes produced today. The company then separated from Nippon Gakki Co. and became Yamaha Motor Company, named after its founder Torakusu Yamaha. The first motorcycle, designated YA1, rolled off the production line in 1954. The Yamaha Motor Co. moved forward from that point, introducing innovations like the first automatically mixed lube and fuel system for two strokes, dubbed somewhat imaginatively the Autolube System. The first of the Yamaha dirt bikes was the legendary DT1, this 250cc two stroke was Yamaha's first purpose built dirt bike. The bike made a huge impact on the North American off road bike scene.
Yamaha continued to break new ground with the introduction of the YZ250 in 1975, the first motocross bike to feature a single shock rear end.
The Yamaha dirt bikes range came to the fore again prominently in 1998 with the release of the YZ400F, at its time of release the only serious mid capacity four stroke motocrosser on the market. This bike set the benchmark for the four stroke revolution with all the other major manufacturers scrambling to play catch up with their own four stroke motocrossers. '07 Yamaha Dirt BikesYZ450F/250FUpdates for the '07 YZ450F include new forged upper triple clamps as well as lighter rims and wave type brake rotors. There's also revisions to the clutch and an updated exhaust system. Factory equipment on the bike this year includes aluminium Pro Taper handlebars and a gripper style seat. There's also titanium footpegs as standard. The YZ250F has altered carburetion and ignition specs aimed at increasing bottom end and mid range power. The steering head geometry has been changed on the four stroke 250, it's been moved back by 3mm to help the bike turn quicker. The front brake caliper and master cylinder have also been updated this year to save weight. Both the 250 and 450 have a new oversized barrel clutch adjuster to make it easier to make adjustments on the fly. Again the 250F also gets the Pro Taper bars, gripper style seat and the titanium footpegs.
YZ250/125 The two stroke 250 has had some work done on the forks for this year, the thickness of the outer and inner fork tubes has been changed and the damping settings have been revised. The rear suspension has new aluminium components to save weight and the settings have been changed to match the altered front forks. The 125 for '07 has also had the same mods as the 250 done to the suspension front and rear. There have been changes made to the ignition map and silencer for improved bottom end and mid range power. The 125 and 250 have a new stainless steel clutch cable for durability, they also have the works style clutch adjuster, Pro Taper bars, gripper seat and titanium footpegs that are standard equipment on the four stroke bikes as well.
YZ85 The baby racer of the YZ range is not short of features, the bike has a six speed transmission and fully adjustable 36mm Kayaba forks and Kayaba rear shock. It also has a lightweight semi-double cradle steel frame.
The stable of Yamaha dirt bikes are already competitive, these new updates are nothing major, just revisions aimed at hopefully making a good thing even better. (All photos courtesy of Yamaha-Motor.com) Click here to check out all the specs and photo galleries for the '07 Yamaha dirt bikes. Click here to go back to our Home Page. Please note that to protect our younger visitors to Motocross 101, SafeSearch is turned on in these search results.
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