Let’s face it, Yamaha’s YZ450F has gotten a bad rap. Blame James Stewart’s less-than-stellar results on the bike in 2012 prior to his leap to Suzuki, combined with slanderous comments on Internet forums. But guess what? The “backward” design is back, and Yamaha’s engineers, led by Mr. Hiroshi Ito (WR450F project leader, too) still believe in the rearward-leaning cylinder with intake at the front and exhaust at the rear.
Highlights of the all-new engine include reshaped intake and exhaust ports with larger-diameter valves. The piston now has two rings instead of three. Wet-sump lubrication is now used, and the smaller engine is placed farther forward in the frame.
A good indication that the ’14 YZ is significantly more powerful is the 20-percent-stronger clutch. The five-speed transmission features new ratios; the gap between second and third is closer while the jump from third to fourth is wider. A new gear-position sensor tells the ECU to select individually optimized maps for first through third gears.
Chassis updates include an all-new frame, subframe, shock, fork settings, fuel tank with hidden filler, revised and easier air-filter access and fresh bodywork. Next step? Get it on the track with the current class leaders (Suzuki, KTM and Honda) and see if these changes add up to success.
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