Q: FIRST AND FOREMOST, IS THE 2015
YZ450F BETTER THAN THE 2014 YZ450F?
A: Yes, but the MXA wrecking crew is at a loss as
to why it is so much better. Nothing on the spec sheet
would lead one to believe that this is a qualitatively
improved machine. But, it is.
Q: WHAT ARE THE MAJOR CHANGES THAT
YAMAHA MADE TO THE 2015 YZ450F?
A: It is important to remember that the 2014
Yamaha YZ450F was totally new from the ground up;
only the rear wheel, front fender and brakes were left
over from 2013. We give you this info as a lead-in to
the fact that we never expected Yamaha to make any
changes to the 2015 YZ450F. No motorcycle manufacturer
has the R&D budget to build a totally new bike one year
and then significantly change it the next year. As a rule
of thumb, bikes have to live through a four-year development cycle, which means that the 2014 Yamaha YZ450F
should remain basically the same until 2018.
Here is the short and tidy list of what’s new for 2015.
(1) Forks. The Kayaba SSS forks have new valving,
stiffer fork springs and a redesigned fork-tube wall
thickness for more resilience.
( 2) Rims. The Excel rims are black anodized and
equipped with Dunlop Geomax MX52 tires.
( 3) Airbox. Instead of bolts, Yamaha holds the airbox
cover in place with three, quick-release, quarter-turn Dzus
( 4) Mapping. The Electronic Control Unit (ECU) has
been remapped for 2015.
( 5) Throttle return spring. The spring on the EFI
throttle body has been lightened 20 percent for easier
( 6) Motor mounts. The previous aluminum lower-motor mounts have been replaced with reshaped steel
plates to allow a little more flex in the front of the frame.
( 7) Gearing. The rear sprocket went from 49 teeth to
( 8) Gear-stop lever. To aid in shifting, the gear-stop
lever has been changed to a roller type.
Q: WHAT DO THESE EIGHT RATHER BASIC
CHANGES FOR 2015 ADD UP TO?
A: Right off the bat, we can discount the black rims,
Dzus fasteners, throttle return spring and gear stopper
as major contributors to the 2015 Yamaha YZ450F’s
improved feel. With four changes eliminated, let’s analyze
the remaining four.
KTM 350SXF 2015 YZ450F
Mirror image: It doesn’t look a lot different
than last year’s YZ450F, but something
has changed under the hood.