Yamaha YFZ450

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The Yamaha YFZ450 is a high-performance, four-stroke all-terrain vehicle (ATV). Introduced in 2003 as a 2004 model, it was a huge leap forward relative to its competition. It uses many light-weight materials to give it the lowest dry-weight (350 lbs.) of any 450-class sport ATV. Its only other competitor at the time of its introduction was the Honda TRX450R.

This ATV was considered "revolutionary" and the "biggest step toward an off the showroom floor race ready ATV available by any the four major Japanese manufacturers". By the end of the 2004 ATV racing season, three of the four National Championships were claimed by riders riding the Yamaha YFZ450: Keith Little, Brandon and Bill Ballance and Brett Oakley.[1]

Model Year Changes[edit]

The YFZ450 model as a whole has not changed much; however, many small changes have been made throughout its run.


  • First model-year, introduced all-new 439cc motor


  • Banana pipe introduced
  • Hot start level plug changed from rubber to aluminum
  • Internal oil lines
  • YFZ also sold in a Special edition for the first time


  • New crankshaft with increased stroke to 63.4mm (up from 62.0 mm. This made it a true 449 cc. Previously a 439 cc engine
  • Larger capacity radiator
  • Titanium heat-shield
  • Longer steering stem, revised handlebars, and thicker padding in seat
  • Aluminium rear grab-bar replaces steel design
  • Aluminium front bumper to replace steel design
  • Replaced the swingarm with a twin row bearing, round-housing swingarm which made adjusting the chain easier
  • Twin-piston rear brake calliper
  • LED taillight
  • Revised head design (very slight difference, parts interchangeable among years 2004-2008)
  • Revised carburetion, and ignition timing
  • New tire design
  • Longer travel rear shock
  • New front suspension
  • Changed from 10mm to 12mm diameter tie rods


  • ProTaper aluminium handlebars
  • Revised front brake master cylinder and lever
  • Drilled rear brake disc
  • Internal oil jet to lubricate piston bottom
  • Improved clutch
  • Better shocks with high and low speed adjustment.


  • 2009 YFZ 450R for MX
  • Fuel injection
  • Better suspension 80% bigger reservoirs longer travel
  • Aluminium steel hybrid frame
  • 405 lbs wet


  • 2010 YFZ 450X for XC
  • less suspension travel
  • 400 lbs wet weight
  • dropped the YFZ 450


  • Front shocks replaced with ones similar to the 2006 Raptor 700
  • Different cam profiles and timing to make more low to mid-range power
  • 42mm carburetor to make up for loss of top-end power from the milder cam profile
  • Different taillight; now very similar to the 2004-06 banshee


  1. ^ ATVRiders.com