Flat Track Racer

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.


There has been no one on the top level campaigning a YFZ450 for years in this discipline, so Rath had nothing 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.

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 carbon fiber tie-rods with aluminum rod ends. Stock is all steel. The steering 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 18×5.5-10 Hoosier RD12 compound tires up front. In the rear, he uses 18.5×9-10s. 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.

The seat has been lightened and lowered, as well as the subframe. The subframe also has a new bracket that helps hold up the raw air filter element. The stock airbox has been removed for added weight savings and more power. The stock plastic has also been trimmed for less wind resistance and weight. Looking closely at the machine you can also see the Fourwerx Carbon complete titanium fastener kit replacing most of the stock steel nuts and bolts. More Fourwerx Carbon products, including a hood scoop and seat cover, were employed. Even the electronics were trimmed down by Paul Turner to simplify things and save weight. There’s no need for headlights and all the wires it takes to operate them on a machine like this. Additionally, a lighter Shorai battery was installed.


To get more power out of the stock motor, Rath sent the head to Dasa Racing. They performed a complete CNC port job, throttle body bore, installed their national TT-spec cams, and very high-compression, 14.1 piston. On the lower end, the transmission parts were micro-polished to make smoother shifts and better power delivery. Dasa also develops their air filter and complete exhaust systems for each engine package. And, Rolly Bartell tuned the Vortex fuel controller. The motor is actually mounted with lightweight brackets that save an additional 3/4 pound. To get power to the ground, Rath is relying on a complete Hinson clutch setup with a Works Connection clutch lever.

For gearing, Daryl and most guys start with a 14/37 setup and adjust depending on the track. Rath’s sprockets are from Rebel Gear and made of aluminum in the back and steel up front. The chain is a DID O-ring 520 chain.

Rath’s project is also a tool to display some of Rath’s signature products, like their carbon fiber sway bar, front bumper and nerf bars. This particular set has very thin string, like webbing, for even more weight savings and wind penetration. Those SS-series TT nerf bars are also outfitted with Rath’s huge Monster pegs ($479) mounted with aluminum Pro Peg mounts ($200), which help save another 2 pounds. In total, Rath shaved over 55 pounds and heads to the starting line on this machine weighing in at 348 pounds.

Being the newest machine out there, the Yamaha has not taken an overall win yet but has been competitive. Even at 46 years old, Daryl Rath is not only competitive on anything he races, he’s innovative and continues to bring never-before-seen products to the ATV world. If you want any of the products he offers, give him a call at (320) 234-7223 or visit Rath Racing’s online store at www.rathracing.com.

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