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 resistan
New Yamaha YZ250F 2009 Reviews and Specification