KTM DESERT RACER: BEHIND THE BUILD

Making the uncomfortable comfortable—that is the task at hand when racing through the desert for hundreds of miles at over 100 mph. It may sound simple, but it is truly an impossible task—or is it?

The Best in the Desert (BITD) American Off-Road Racing Series is a famed one that started back in the 1980s by desert racer Casey Folks. It began as a motorcycle-specific series, but in the late 1990s came the introduction of cars and trucks, and thus a shift in race formats and course layouts. BITD races are widely considered the fastest off-road races in North America. They are held in the Nevada, Arizona and California deserts, covering hundreds of miles per race. The Kilmartin Racing/3Bros KTM team built up a special 2021 KTM 450SX-F in their quest to defend the Open Pro-class championship against the likes of the factory teams.

Hayden Hintz at speed aboard the championship-winning Kilmartin Racing KTM 450SX-F. Making the uncomfortable comfortable—that is the task at hand when racing through the desert for hundreds of miles at over 100 mph. It may sound simple, but it is truly an impossible task—or is it?

The most unique mod to the Katoom is the transmission. In 2020, KTM changed transmission vendors and now uses Pankl components in its SX/XC models. With the change, there is no option to add a sixth gear to the five-speed transmission. That leads to a big problem, as reaching top speeds of well over 100 mph isn’t as feasible nor as easy on the motor without that crucial gear. The solution? A 2019 XC-F five-speed transmission with an added EXC sixth gear. The mod is a simple plug-and-play; it’s the same transmission used in the previous year’s BITD Triumph.

Kilmartin Racing had one goal in mind when building this 450SX-F—defend the BITD Open Pro Championship with both speed and consistency.

 

To match the transmission, gearing ranged from 14/48 to 15/48, depending on the event, with speeds topping out right around 111 mph with a 15T countershaft sprocket installed. The sixth gear adds the obvious top speed, but it also allows the riders to race in a lower rpm, which in turn smooths out the bike’s handling—a big plus when looking for comfort.

Fueling the bike for most of the year was an IMS Products 4.5-gallon fuel tank and dry-break system. The extra-large tank extends the bike’s range to comfortably reach 115 high-speed miles without refilling. Most of the races take place on fast and smooth fire roads and sand washes, and the gas tank actually helps the KTM’s handling for lightweight riders. The added weight over the front of the bike keeps it planted and stable in fast chop and rocks, a la the famed XR650R in Baja-like conditions. Tighter terrain and slowing the bike down get tricky, but overall the larger tank is a positive at most races.

Fasst Company’s Flexx handlebars damp vibrations and impacts, adding comfort for the long-distance races.

 

Adding comfort to the beast, Factory Connection-valved WP XACT Pro forks grace the front end. Similar to the gas tank, the added weight of the spring forks keeps the front end planted to the ground. The coil-spring components also provide a more consistent feel throughout the races. Typical start times for the BITD races are at sunrise, and races can last up to eight hours. In testing with the air forks, we’ve seen fork air pressure rise nearly 10 psi over the course of a race due to the ambient temperature increasing tenfold over the long duration of the race.

GPR’s new V5D Stabilizer lessens fatigue and helps keep the bike in a straight line so the riders don’t have to.

 

Out back, a stock shock with KYB-style valving and components is paired with a Pro Circuit linkage system for a progressive feel that is designed to take on bigger impacts. When setting up the bike, the duo opted for a stiffer overall suspension setup for hitting larger whoops or G-outs unexpectedly. The stiffer setting offers added safety, and when racing at over 100 mph, safety is the first priority.

Traction is at a premium in the desert, especially when pushing the limits, speed-wise. Kenda tires and Nitromousses fill out the Dubya wheelsets. The tire of choice up front is a Kenda Washougal II for its durability and performance. The two were able to run even the longest races at 500 miles on just one front tire with no swaps needed. The Washougal II also works well and holds a straight line under braking and across the diverse terrain of sand, rocks, hardpack and more. The rear tire choice varied throughout the year, depending on the race.

IMS Products’ 4.5-gallon fuel tank is something you’d think you see on an adventure-style dual-sport bike, but it served as an asset in the fast BITD races.

 

For long-distance races, like the Silver State 300 and Vegas 2 Reno, which consist mostly of hardpacked fire roads, Kenda’s K270 dual-sport tire is the go-to. The longevity of the tire is unmatched, and for the terrain, it hooks up very well under acceleration over more traditional moto tires. For shorter distances and sandier races, Kenda’s Parker DT desert tire offers durability and performance and instills confidence. To handle the constant high speeds, oversized Nitromousses are used, as they resist breaking down under the immense heat and stress they endure.

Seat Concepts’ Comfort seat provides just that—added comfort for eight-hour days in the saddle.

 

Other than the special transmission, the motor is kept stock on the KTM. Even for these high-speed races, the 450cc engine produces enough power, and sacrificing any durability isn’t worth the squeeze; however, to safely get a little more out of the bike, a blend of Moto and SP3 fuels from F&L Racing Fuel is used to help achieve more pulling power, a slightly higher top speed and more consistency with the bike. Running 50/50, SP3 is an oxygenated, leaded fuel with an octane of 113, and Moto is an unleaded fuel with an octane of 95.5. This blend of fuel helps pull the tall gearing run at most races and even increases the top speed 2–4 mph. A Pro Circuit T-6 stainless steel exhaust system completes the motor package and smooths out the power, making it easier to ride for long periods of time.

A Pro Circuit T-6 stainless steel exhaust smooths the power delivery with a durable, lightweight package.

 

The final pieces to the comfort puzzle are in the cockpit. Seat Concepts’ Comfort seat looks like it belongs on a dual-sport rather than a race bike, but it serves two functions. First, it’s more than comfortable to sit on, and you spend most of your time sitting on the seat in a BITD race. Second, the wider platform helps the riders squeeze the bike with their legs better, which lessens upper-body fatigue and gives them more control of the bike. A GPR V5D Pro kit steering stabilizer keeps the front end tracking straight and is a must for high-speed racing. Last, Fasst Co. Flexx handlebars with A’ME grips complete the package in the quest for maximum comfort at warp speed.

No desert bike would be complete without some of the necessary protective pieces, and this Kilmartin Racing 450SX-F is no different. An assortment of TM Designworks products grace the bike in the form of a beefy plastic skid plate and their signature Slide-N-Guide kit. They can easily get a whole season out of these components, and they offer more protection than most other options they’ve tested. Bullet Proof Designs’ swingarm guard and rear disc guard assist in keeping the bike in one piece and moving as it should.

Every piece on this bike has been tested and approved by both Hayden Hintz and Trevor Hunter and, in the end, it was good enough to best the field, as they successfully defended their BITD Open Pro-class championship. To most, the bike setup is dubious, as they note the giant 4.5-gallon gas tank, the Comfort seat and dual-sport rear tire, but it all serves a purpose—making the uncomfortable comfortable.

Comments are closed.