It’s that time of year again. Even though 2008 is not yet half over, manufacturers are already rolling out 2009 motorcycle specs. Yamaha has jumped the gun on its Big Four competition by unveiling its 2009 YZ dirt bike lineup.
Of the two four-strokes, the smaller YZ250F has had the most work done for ’09. The single-cylinder 4-stroke mill is unchanged – except for a black magnesium valve cover, but the little Yamaha thumper does source a new exhaust. A revised Titanium headpipe is 60mm longer and the muffler is shortened 50mm and lightened 180 grams (0.4 lbs). Combined with new ignition mapping, Yamaha promises the new exhaust improves low-end power and throttle response.
A new clutch basket assembly, utilizing rubber instead of coil spring dampers, is lighter and easier to maintain. And pulling in the clutch should be more convenient with a redesigned lever assembly, with the lever itself shorter and offering a greater range of adjustment.
The ’09 250 also sees modifications to the rolling chassis. Up front a new Bridgestone M403A tire is connected to the KYB SSS (Speed Sensitive System) fork with revised settings and set in a new top triple clamp.
The YZ450F shares many of its little siblings changes, including a new swingarm, rear hub and top triple clamp.
Even more changes appear out back, with a ligher (350 grams, 0.77 lbs) hydroformed swingarm featuring reduced twist and vertical rigidity but increased horizontal rigidity. The swingarm is mated to a revised linkage and rear shock which now uses a steel spring instead of titanium. The shock settings, like the fork, are also modified. Also new is a lighter (265 grams, 0.58 lbs), more compact rear hub system with a larger diameter axle (25mm compared to 22mm).
Other ’09 tweaks are shared throughout most of the YZ lineup. A more compact brake hose holder replaces a larger steel design up front, with a new D.I.D. gold-colored chain sprucing up the rear. Another minor difference is a new seat cover pattern, which Yamaha claims improves grip and is more stain resistant.
Changes to the 450 YZF are similar to the 250, with the following exceptions: No changes to the exhaust, tires or suspension units. Instead the big news is, drum roll, the number of stator mounting points have increased from three to four! Okay, nothing revolutionary there, but first and third gear shift fork bars are 4mm longer to improve shifts between second and third.
After that the revisions are essentially identical to the 250F, with a new swingarm and linkage, rear hub and top triple clamp. Also modified is the clutch lever assembly, front brake hose holder, gold chain and seat surface.
YZ250, YZ125 and YZ85
The YZ 2-strokes haven’t gone the way of the Dodo quite yet, with Yamaha still putting out the YZ250, 125 (above) and 85.
In 2005 the 2-stroke YZs made up 50% of Yamaha’s dirt bike sales. Now the little smokers account for less than a quarter of the marque’s off-road numbers. The evaporation of the 2-stroke market has contributed to Yamaha’s recent drop in dirt bike sales, but unlike many of the other off-road manufacturers – some having dropped 2-strokes altogether – the Tuning Fork label remains on three YZ buzzers.
Little has changed to the YZ lineup, with the YZ85 just getting new graphics. The YZ125 and 250 received upgrades mirroring their 4-stroke counterparts: the new aluminum brake hose holder, D.I.D. gold chain and new seat cover pattern. Both bikes are now fitted with the same D742FA Dunlop front utilized on the YZ450F, with the 125 also getting a lighter (200 grams – 0.44 lbs) Dunlop D756G rear tire.