WHAT IS IT? A replacement throttle body for most
modern motocross bikes.
WHAT’S IT COST? $1499.00 (throttle body kit with
Vortex black box).
www.r1dean.com or (562) 864-8218.
WHAT STANDS OUT? Here’s a list of things that
stand out with the R&D Genius throttle body.
(1) The idea. R&D’s stroke of genius was to invent a
rotating gate design. Instead of a flat slide or a butterfly valve, R&D designed an elliptical barrel that rotates
inside the throttle body’s venturi. The elliptical barrel
rotates completely out of the way at full throttle, and
because of its smooth shape, the air flows over it with
( 2) Bad butterfly. The common throttle body uses
a butterfly valve to open and close the venturi of the
throttle body’s bore. Butterfly valves are cheap, but they
aren’t aerodynamic. No matter whether the throttle is
open or closed, the butterfly always creates turbulence
that lessens fuel velocity.
( 3) Maximum velocity. When you open R&D’s
elliptical barrel, it rotates completely out of the way.
And by full throttle, it not only disappears but becomes
the smooth bottom surface of the throttle’s bore.
( 4) Delay. MXA first tested R&D’s Genius throttle
body two years ago, but only a handful of people ever
got to use it because Dean couldn’t find a machine shop
that could mass-produce the complex throttle body. Now,
R&D has solved its production problems and is shippimg.
( 5) Flow. First and foremost, the Genius throttle body
is designed to improve low-end power and partially open
throttle response and pickup through the midrange. The
smooth-flowing characteristics of the Genius design have
the biggest effect when engine vacuum is low and fuel
misting is compromised. Once the throttle body is wide
open, the Genius barrel is completely out of sight.
( 6) Performance. Every MXA test rider liked the
throttle response of the Genius on both our CRF450
and YZ450F. It smoothed out any irregularities, boosted
horsepower and made the bikes easier to ride. It was a
clear-cut improvement in the brain-to-throttle equation,
which is probably why the Geico Honda team used it
and Doug Dubach had it on his bike when he won the
World Vet Championship.
WHAT’S THE SQUAWK? This isn’t a cheap mod. It
involves a complex, CNC-machined piece and a new
electronic ECU (supplied). It is a serious racing product
that improves throttle response and power, but since it
isn’t visible to the naked eye, it’s not for the status
conscious guy. It is designed to take a hopped-up engine
to the nth degree
If you think you have done everything possible
to make your bike faster, you haven’t
scratched the surface until you’ve tried the
R&D Racing Genius throttle body.
R&D GENIUS THROTTLE BODY
MXA TEAM TESTED