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"Transworld Motocross", February 1, 2013

YAMAHA YZ450F PERFORMANCE PACKAGE

APPLICATION: 2010–2013 YAMAHA YZ450F

R: JOHN SIMANOVICH

MAEDA

In the years since Yamaha introduced the radically different 2010 YZ450F, the machine has received feedback that wildy radically from one end of the spectrum to the other. While some riders (most often taller or larger pilots) love the machine, others have struggled to come to grips with the unique handling characteristics and ergonomics of the YZ450F. For the most part, a lack of front-wheel traction and unpredictable front-end handling characteristics are the complaints that most riders have.

As a key R&D test rider for Yamaha, Doug Dubach has likely spun more laps aboard the current YZ450F than anyone, and as owner of Dubach Racing Development, he’s also spent a considerable amount of time trying to improve the performance of the production machines. DRD has garnered plenty of praise in recent months for its Engine Relocation and Radiator Lowering Kits, so we dropped our 2013 Yamaha YZ450F test bike off at their Norco, California, offices and asked for the treatment.

MASS CENTRALIZATION

Consisting of two swingarm pivot collars, two engine mounts, three exhaust mounting studs, and a header pipe spacer, the Engine Relocation Kit moves the YZF’s powerplant 2.5 mm forward in the chassis, which in turn shifts the bike’s front-to-rear-weight bias and places more weight up front. Installation requires some mechanical skills but is not so difficult that it should scare casual mechanics away. We watched Dubach install the kit in less than 30 minutes, so we’d assume that an hour for a first-timer would be a conservative estimate.

To further enhance the better mass centralization of weight, a DRD Radiator Lowering Kit was also installed. We’ve used this kit plenty of times in the past on previous YZFs and know that the kit is a snap to install, as it involves only four small lowering linkages that drop the radiators 27 mm.

MANNERS, MANNERS

On the track, the two DRD kits yield performance gains that are easy to feel, right from the first lap. In rough corners where the stock bike would suffer from untrustworthy front-end manners under braking, the modified machine enjoys a much more planted feel up front with ample, predictable front tire traction. The mid-corner vagueness is eliminated altogether, as the YZ450F becomes easier to lean into a directional change. The lower, better-centralized mass actually makes the bike feel several pounds lighter, and the bike’s tendency to push the front end when accelerating hard out of a flat corner is eliminated.

Simply put, the $149.99 Engine Relocation Kit and $99.95 Radiator Lowering Kit can do more for the Yamaha YZ450Fs handling characteristics than much-more costly suspension revalves, different offset triple clamps, or shock-lowering linkages.

ONE STEP BEYOND

While we were at DRD the first time around, we spotted a very different exhaust system mounted on Dubach’s personal race bike. Instead of exiting the rear of the cylinder and making the “tornado” loop before exiting out the rear of the bike, the header pipe wrapped forward and around the front of the cylinder on the left, before exiting on the right like a traditional exhaust. According to Dubach, the design was “suggested” by Yamaha, and a few aftermarket exhaust companies have been urged by the factory to build such systems for their factory-backed race teams. The design carries the mass-centralization theme even further as the weight from the stock “tornado” exhaust is relocated further forward toward the center of the bike; furthermore, the muffler is located nearly six inches further forward on the chassis.

After seeing our faces light up, Dubach offered to install one of the not-for-sale systems on our test bike, as well. To accommodate the different header pipe shape, the left-side radiator was modified to provide extra clearance.

On the track, the wraparound exhaust produced even better power with more low-end snap than the standard DRD system, but the real benefits were gained in the handling department. Even more so than with the Engine Relocating and Radiator Lowering Kits alone, the bike took on a whole new personality with a light, flickable feel and a front end that tracks with the best of them.

Sadly, the wraparound exhaust will not be available for sale to the public, but if nothing else, the design of the system alone is a hint that Yamaha has some big changes in store for the 2014 YZ450F...

dubachracing.com

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