RATHVARNA

We used a 2018 450 FC Husqvarna frame and engine transformed it into a trike. Using custom CNC parts as well as a fabrication to the frame and subframe. This was featured in the February 2020 edition of Dirt wheels magazine.

Yamaha YFZ450R hybrid ATV with ’17 KTM 450SX engine!

This build derived from wanting more than what the current ATV market could offer, Daryl used a YFZR frame because of how well it can handle, then he added parts to make it very lightweight. Parts like, Rath Racing titanium a-arms, swingarm, tie rods, linkage, and also billet aluminum pieces.

The heart of this machine is even more impressive. Daryl bought a 2017 KTM 450SX Factory Edition dirt bike and took the engine, fuel injection and wiring out. He then fabricated the needed parts to mount the KTM engine into the YFZR chassis. It’s built for TT racing and believe us when we say it’s one of the most powerful machines we’ve ever ridden!

ATC250R

The two-stroke engine was utilized in almost every racing ATC back in the 1980s until four-stroke engines began to make their appearance. Daryl found a 1985 Honda ATC250R and began modifying the whole bike, starting with the powerplant. Rath had CT Racing massage the cylinder porting and polished the head for $425. VP C12 race fuel must now be used in the Honda Short Course tank that is designed to let the handlebars turn further than stock. To provide the right flow of fuel to the engine is a Keihin PWK 38mm carburetor. A $48 K&N air filter was installed without an airbox to allow the maximum amount of airflow to the motor. To help the fuel and air mix is a $180 Boyesen Rad Valve reed cage with an NGK spark plug to create combustion. Check out the full story in the July 2016 copy of dirtwheels magazine.

2014 YFZ450R

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.

Complete story in the July 2015 Dirt Wheels Magazine.

"JUST MAYBE"

We know this doesn’t have anything to do with a UTV or ATV, but it does have four-wheels; right?! Plus, the “Just Maybe” tractor built by Daryl Rath (owner of Rath Racing) and his late father has a twin 800cc and a twin 700cc Polaris snowmobile two-stroke engines side by side making it a quadruple cylinder!