The YZ450F is an enigma because it feels the most powerful but the dyno shows it as being the most anemic. We couldn’t convince B.C. it’s down on power.
Clearly, Yamaha has done a phenomenal job of making the YZ450F feel stronger than the dyno indicates, while Honda and Suzuki have managed to tame some monster numbers.
More telling than peak numbers is the amount of horsepower and torque delivered in the heart of the powerband. All three have similar curves on the dyno charts, each dishing out the majority of internal combustion punishment between 7,500 and 10,000 rpm, right where a racer likes to keep the rpm.
The CRF450R and RMZ-450 were close, but Honda’s motocrosser delivered the most impressive stats, topping 47 horsepower from 7,500 revs all the way to 9,700 rpm where it tapers slightly as it nears 10,000 rpm.
The RM-Z also dished out impressive performance numbers, posting more than 47 horsepower from 7500-9100 rpm, when it falls to 46 and tapers off more severely as the Rs reach 10,000 rpm. The YZ450F is the most anemic and barely climbs above 45 at 7,500 rpm and never climbs much higher. Honda and Suzuki should be praised for dishing out horsepower numbers and doing so in a manner that allows the pilot to put that power to the ground in a manageable manner.
Handling all that horsepower are two different chassis philosophies. Honda and Suzuki opt to utilize an aluminum perimeter frame, while Yamaha stays with the tried and true steel chassis. Luckily for you, the reader (unlucky for us), Mother Nature delivered some of the most difficult conditions to test this trio in. Oregon’s annual spring showers turned into a week-long deluge the week before our test, which was followed by unseasonably hot temperatures. Ultimately, the bizarre weather patterns turned the RVMX track into a seemingly delectable candy bar, crunchy on the outside and gooey in the middle (but without all the sugar). If ever the suspension and chassis would be put to the test, it was on the surface at RVMX. Lucky for us we had talented little MX groms with elastic bodies that could push this trio through just about any condition and do it with maniacal grins smattered across their faces.
Mason Harrison felt the Yamaha was the slowest steering of the bunch, but still offered impressive racing capabilities.
In 1997 Honda revolutionized motocross handling when it introduced the aluminum perimeter frame on the CR250. Since that time it has continued to enhance, tweak, and improve upon the initial design. Honda caught flack early on for the sometimes unbearable stiffness, but in the subsequent years its perseverance paid huge dividends and few will dispute the advantages of the aluminum perimeter frame. Although an aluminum frame is generally lighter than a steel chassis, the CRF and YZ both logged the same weight at 233 lbs, while the RM-Z is just one pound heavier at 234.
A good chassis allows the suspension to function up to its performance capabilities while providing plenty of feedback to its rider. Honda managed to fix the initial problems with its aluminum perimeter frame and is now is one of the most coveted components on the CRF450R. In fact, it works so well that Suzuki opted to mimic the design and fitted the RM-Z with a similar aluminum perimeter frame. Yamaha remains the only manufacturer utilizing a steel perimeter skeleton in this class for 2005, but it doesn’t hinder the performance of the YZ450F.