Dirt Wheels - October 2014

❏ In most series, we see a pretty good mix of race machines by all manufacturers. However, for some reason, Honda has virtually dominated all of the top spots in Extreme Dirt Track (TT) racing for the last decade. Well, Yamaha and Rath Racing want to change that. No, they are not hiring away the top guys or dumping a bunch of money into sponsoring the sport; they are going about it another way. Rath Racing is building up a top-level 2014 Yamaha YFZ450R just to show it can be done. Yamaha hopes their effort will pay off and attract more of these flat trackers and their friends to the brand, and Rath is up to the challenge.

STARTING FROM SCRATCH

There has been no one on the top
level campaigning a YFZ450 for years
in this discipline, so Rath had noth-
ing to go on except years of building
many other brands of competitive
flat-track machines. “So the basics
are the same,” Daryl Rath (owner
of Rath Racing) tells us. “You need
high horsepower and low weight to
be fast here. We know what it takes
to be competitive in TT, so we just
had to find ways to shave weight and
build a fast YFZ450R. Chad Wienen is
doing it on the MX scene, so we knew
it could be done.

TIPPING THE SCALES

The stock YFZ450R weighs in at just over 400 pounds with 2. 5 gallons of gas. After nerf bars, larger footpegs, steering stabilizers and other goodies are installed, a typical MX YFZ450 hits the track at about 420 pounds. In the extreme flat-track world, exotic materials like titanium and carbon fiber are more prevalent, and most of the pros’ quads weigh about 350, so that is the mark Rath was shooting for with this build. To achieve this goal, steel had to be replaced by aluminum in a few key locations, along with a couple other secrets he filled us in on.

Up front, Rath built new lower chromoly steel A-arms and paired them with a set of aluminum uppers.

The complete set retails for $925. The
tie-rods were replaced by $325 car-
bon fiber tie-rods with aluminum rod
ends. Stock is all steel. The steer-
ing stem was also replaced using a
non-welded, bolt-together aluminum
stem that is three-fourths lighter ( 2
pounds). The spindles are stock, but
the hubs are Rath’s own hubs that
produce less drag and help the quad
corner like it’s on rails. Rath sells
these $430 (a pair) hubs for 4/144- and
4/156-bolt patterns. Daryl uses 18x5.5-
10 Hoosier RD12 compound tires up
front. In the rear, he uses 18.5x9-10s.
All four tires are mounted on DWT A5
wheels.

Out back, the stock swingarm was replaced by a chromoly swingarm that measures 2 inches shorter than the stocker. It costs $925 complete with a bearing carrier. A Rath Racing lowering link ($325) allows the quad to still ride smooth, even though the swingarm and shock are shortened. The combo really makes the YFZ450R transfer weight well and get off the starting line fast and hook up out of the corners. The axle and aluminum rear hubs are all Lone Star Racing products.