The Steahly flywheel weight makes the power more usable and pays extra dividends in helping plant the front wheel to the ground coming out of corners.
The MXA test riders fine-tune the feel of the YZ450F clutch by mixing and matching
the combination of the YZ450F’s two different types of clutch plates.
JGRMX’s shock linkage can be adjusted across a 4mm range. We go 2mm longer.
HEAVIER FLYWHEEL WEIGHT
FOR BETTER HANDLING
This might sound strange, but one
of the best-handling mods that we
made to the YZ450F was to put a
Steahly 9-ounce flywheel weight on it.
In stock trim, the YZ450F is aggressive at first crack of the throttle, which
leads to unwanted wheelspin in slick
or slippery situations and, conversely,
jumpiness in tacky situations. Deep
sand and fast pros may prefer that
hit, but most MXA test riders wanted more throttle control and broader
power. After racing with and without
the Steahly-modified flywheel, every
test rider was generous in his praise
of the benefits of the heavier flywheel.
The goal was to make the YZ450F feel
torquey, smooth out the powerband
and focus on manageable power.
The Steahly YZ450F flywheel weight
isn’t a bolt-on project (as it requires
gluing and baking), but Steahly will
do the hard work for you for a small
surcharge. For more information, go to
Of all of the production Japanese
clutches, the Yamaha’s is the best. It
lasts longer and feels better than anything that Honda, Suzuki or Kawasaki
have to offer. The cheapest way
to improve the YZ450F clutch is to
understand that the eight-plate clutch
pack has two different types of clutch
plates—grippy and standard. In stock
trim, the clutch has three grippy
clutch plates (part number 5VP-16321-
00) and five standard clutch plates
(part number 5PA-16321-00). If you
want a stronger clutch, replace some
of the standard plates with grippy
plates. You can replace all five or just
two or three to modulate the feel. One
caveat: the standard plates should be
used in the innermost and outermost
positions in the clutch stack. That
said, the YZ450F is still not up to the
standards set by KTM. To help the
clutch survive, we added stiffer Pro
Circuit clutch springs. For our AMA
Pro test riders, we went with a complete Hinson clutch.
ADJUSTABLE JGR SHOCK
The YZ450F is a bike with a strange
mix of handling sensations—some of
them caused by the stinkbug stance.
Our fix was to install adjustable
JGRMX shock-link arms. JGR links can