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 manufacture 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. '09 Yamaha Dirt BikesYZ450F/YZ250FThere have been an array of subtle updates to the YZ450F for '09, the swingarm has been redesigned to make it lighter and offer better performance when cornering and improved traction. The rear suspension linkage has also been reworked to match the new swingarm. The rear hub has also changed to accomodate a 25mm rear axle as opposed to the old 22mm item, it's supposed to improve rigidity to work in with the new swingarm (it will also annoy anyone who wants to use their spare wheels in their new bike). The top triple clamp now has two sets of bar mounting holes, this offers four different mounting positions for the handlebars. The 450 comes with Pro Taper bars fitted as standard as well as a new gripper style seat cover. There's the usual graphics update and also a gold side plate drive chain just to look nice.
The YZ250F also scores the new swingarm for '09, as well as the reworked suspension linkage and the new rear hub to take the 25mm axle. The exhaust system is changed, the titanium header is 60mm longer to improve bottom end power and the muffler is 50mm shorter to improve bottom end throttle response. There are changes to the clutch internals and the jetting and ignition mapping have been revised to work in with the new exhaust. Both the 450 and 250 have a new aluminium brake hose clamp which is said to greatly reduce its weight. It's a brake hose clamp, just how much did the old one weigh? The 250 also has the Pro Taper bars standard and the gripper seat cover and gold chain. YZ125/YZ250 The senior two strokes have had very little updates again this year, both bikes get a gripper style seat cover, the gold plate drive chain and the aluminium brake hose clamp. Both bikesalso have 48mm KYB forks up front and KYB rear shock. They both also have the Pro Taper bars as standard equipment. There are still quite a few two strokes around at racetracks and if you're forking out your cash for one then you would expect at some point the manufacturer would actually be doing some research and development instead of just putting new stickers on the same bike each year.
YZ85 The baby of the Yamaha dirt bikes is also a bit light up for updates in '09, the bike still has the KYB 36mm inverted forks up front and the Kayaba link type shock on the rear. The 85 caters from novice riders all the way up to expert with fully adjustable suspension front and rear and a single backbone, double cradle frame for improved handling and cornering. The 85 runs digital CDI ignition and a six speed transmission.
(photos courtesy of yamaha-motor.com) Click here to check out all the specs and photo galleries for the '09 Yamaha dirt bikes at Yamaha's website Click here to take a look at the '08 motocross lineup Click here to check out the '07 Yamaha motocross range Please note that to protect our younger visitors to Motocross 101, SafeSearch is turned on in these search results.
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