Q: FIRST, IS KAYABA’S SSS SUSPENSION
STILL UP TO SNUFF IN AN AIR-FORK WORLD?
A: You bet. Compared to the forks on the Kawasaki,
Honda, KTM, Suzuki and Husqvarna, the box-stock
Kayaba SSS forks on the YZ450F are “works forks.” They
are so much better than the new breed of air forks that
it’s no contest.
Air forks have two major advantages over Kayaba
SSS forks: (1) Air forks cost the manufacturers a lot less
to purchase. Why are they cheaper? They don’t have
expensive coil springs. They only have parts-intensive
valving in one leg instead of two, and they are easier
to assemble at the factory. Unfortunately, though they
may be cheaper to produce and install at the factory, the
consumer price does not reflect the cost savings. ( 2) Air
forks are lighter than Kayaba SSS forks. How much
lighter? Well over 2 pounds (based on the fact that there
are no coil springs and one fork leg is effectively an
empty tube filled with air).
How long can Yamaha’s R&D department ignore the
weight and dollar savings just to spec the best forks on
the track? We hope they turn a blind eye to air forks for
a long time.
Q: SECOND, HOW DO THE MAPPING
CHANGES CONTRIBUTE TO THE YZ450F’S
A: Last year the MXA test riders only ran the stock
mapping for one hour before breaking out the GYTR
Power Tuner to pump up the fuel percentages and
advance the ignition timing (to help burn the extra fuel).
Our mapping eliminated the barky hit off the bottom,
pumped up the middle and eliminated the lean stutter.
Thus, it is no surprise that the 2015 Yamaha YZ450F
comes with a version of our 2014 map in stock trim. The
big plus is that 2014 YZ450F owners can achieve the
same powerband results by remapping their bikes.
The 2014 YZ450F’s barky and lean mid-to-top didn’t help
the bike get smoothly through corners, because it had a
powerband that lurched instead of flowed. The new map
allows the front end to stay on the ground on exit instead
of lifting off and ruining the turn.
Q: THIRD, IS ANYONE SENSITIVE ENOUGH
TO FEEL THE DIFFERENCE BETWEEN A STEEL
AND AN ALUMINUM MOTOR MOUNT?
A: You would be surprised how much difference
changing the thickness, sizes, shapes and material for
the motor mounts or head stays can make to a bike’s
Math equation: The real potential of Yamaha’s
centralization of mass theories will not be fulfilled until
the YZ450F loses some weight and bulk.