2009 Yamaha YZ450F

2009 Yamaha YZ450F: The Final Year of the Traditional Carburetted YZ450F

The 2009 Yamaha YZ450F was a refinement of the aluminium-framed generation introduced in 2006 rather than a major redesign. Its familiar 449 cc five-valve engine, Keihin FCR-MX39 carburettor, five-speed gearbox and KYB suspension all continued, with Yamaha concentrating on detail improvements before the radically different 2010 model arrived.

The engine retained its 95.0 x 63.4 mm bore and stroke and 12.3:1 compression ratio. Fuelling still came from the Keihin FCR-MX39, giving the 2009 bike the direct carburetted throttle response associated with this generation. Age-related accelerator-pump wear, jetting and hot-start issues can now affect many examples, so owners working on the original unit can compare options through the MXOwners carburettor reference.

The aluminium semi-double-cradle chassis remained paired with a 48 mm KYB Speed Sensitive System fork offering 300 mm of travel and a Monocross rear suspension system providing 314 mm. Owners servicing the twin-chamber fork can refer to the MXOwners fork oil reference when checking oil specifications and setup.

For Australian-market bikes, Yamaha specified a 120/80-19 rear tyre alongside the familiar 80/100-21 front. Replacement sizing can be checked through the MXOwners Tyre Size Guide, while model-specific chassis and engine components can be identified through the MXOwners Parts Finder.

Historically, the 2009 YZ450F is significant as the last of Yamaha's conventionally laid-out, carburetted five-valve 450s. The following year's machine introduced fuel injection and a radically reversed engine layout, making the 2009 model the final development of an architecture that traced directly back through Yamaha's pioneering YZ four-strokes.