In September of 2013, Kurt Caselli joined the Dirt Bike staff for a photo and video shoot in the sand dunes of the Owens Valley. It would be the last of many collaborations. Three months later, he would be taken in a tragic accident that still brings us to tears.  Mark Tilley wrote this feature on riding Kurt’s two race bikes, which appeared in the November, 2013 issue of Dirt Bike. That magazine went on sale just days before Kurt’s death.

Kurt Caselli on his 2013 rally bike.

Kurt Caselli is one of a kind. He hasn’t followed any predetermined formula for success or taken any other rider’s career path. In fact, no one else has ever done quite the same thing for a living. He divides his time between three different racing disciplines in three different parts of the world. In the U.S., he’s the current Hare & Hound champion. In Mexico, he’s a Baja racer. In the rest of the world, he’s undisputed as America’s top off-road ambassador and a Red Bull KTM factory rally winner. In the often bleak landscape of off-road racing, Kurt Caselli has carved a place like no other.
On the surface, the roles seem freakishly different. Navigating through Peruvian sand dunes on something that looks like a street bike and racing in the desert on a virtual motocross bike would appear to require completely different skill sets. But that’s not really the case. As it turns out, the bikes and the skills required to pilot them have more in common than you might think. To see how much, we got together with Kurt and his KTMs in the California desert. He let us ride the two most exotic off-road racers in the world—his Red Bull KTM 450 Rally bike and his KTM 450SX Baja racer. It turns out that the two bikes have one very important factor in common: they’re very, very good.

Kurt Caselli’s Baja race bike.

Engine: In this area, both bikes are almost identical. As a matter of fact, KTM USA actually bought the engines being used in their Baja machines completely assembled straight from the Austrian factory’s Rally division. The engine is based off the 2012 450 SX twin-cam, carbureted powerplant. Yes, we said “carbureted.” It’s a mystery to us as well. A high-performance Pankl rod and piston are utilized but the stock compression is retained. All the porting is done by factory KTM, matched with Del West valves and factory cams to produce maximum performance throughout the power curve without sacrificing durability. The Baja engines uses a Rekluse Core manual complete clutch, while the Rally engines uses a factory clutch with modifications to improve oiling. Both engines have Duval transmissions for improved durability. To keep the engine cool, the Baja machine has SXS wide radiators that have been modified to use stock hoses just in case the need arises to use a stock radiator during the race. The Rally bike has a single radiator with a built-in electric cooling fan similar to the KTM 690’s stock unit. Both bikes have the capability of running an external oil cooler on the left side of the engine, but the Rally bike runs a larger remote unit behind the front faring under the headlight and navigation panel.
Exhaust: Besides the bodywork, the exhaust is the most noticeable difference between the two. The Rally machine runs a custom Akrapovic system that is similar to down pipes that ran on motocross bikes back in the early ’70s. This type of system is needed to clear the additional fuel tanks on the Rally machine. The Baja machine also runs a custom KTM off-road-performance-specification FMF exhaust, with added reinforcements in critical areas for durability, and the muffler is stuffed with heavy-duty factory packing to prevent blow-out under extreme conditions.

Kurt Caselli’s Dakar Rally bike.

Electrical: The ignition cover is factory built for both machines in order to accept the stator and flywheel from a 350EXC, which has the capability to power a headlight and taillight—items the 450SX engine was never intended to carry. With the additional power output, a larger regulator is needed on both machines, and custom mounting tabs are welded on the frames in the desired locations. Both wiring harnesses require extensive modifications for the custom applications. On the Baja machine, lighting is critical—unlike rallies where the riders rarely race at night, the Baja 1000 is run all night long. With a combination of day-and-night riding, KTM makes all the lighting for the Baja machine with quick on or off capabilities. The CDI unit is structurally the same on both bikes, but the rev limiter is set lower than the stock setting of 11,600 rpm, the Baja machine is 10,200 rpm and the Rally machine is set around 9400 rpm. This is done for durability and controllable power.

Kurt Caselli, riding the dunes in 2013.

Chassis: The Baja and Rally KTM chassis both hold the same 450cc engine, incorporate the use of steel tubing and are orange, but that’s where the similarities stop. The Baja machine is a 2012 KTM 450 SX frame, with the subframe and swingarm modified when needed to fit necessary accessories. The Rally 450, on the other hand, is a completely different configuration and probably a tad overbuilt for the small 450cc engine it carries. Using the frame, subframe and swingarm of the KTM 690 Enduro, the Rally machine utilizes a cradle-less-style frame configuration that is commonly seen on street bikes. The top half of the frame is steel tubing, similar to what is used on the Baja machine, but the lower half that usually surrounds the engine is just a series of aluminum engine mounts that hold it in place but does not surround it completely. As a matter of fact, if the entire lower faring and skid plate is removed, the engine would appear to be just hanging in the frame. This is done on street bikes often because the engine will help increase the rigidity, improve the strength, reduce frame weight and make the engine more accessible for maintenance purposes. Caselli tells us that with removing two front mounts and the rear swingarm pivot bolt, the engine can be removed completely. He would know; during his first Dakar Rally earlier this year, he helped former teammate Cyril Despres do an engine swap.
Suspension: WP handles the suspension duties for both machines, front and rear. All components are handmade in house by WP technicians at their race department in the Netherlands. The Baja and Rally machines use a “cone valve” fork, similar to what is used in Supercross and motocross. KTM/WP feel this damping system gives the rider a more stable feeling than the regular shim-built damping systems. With three different cone shapes available and five different spring rates to choose from, there are many options to adjust the damping for every kind of terrain or rider preference. For Baja, Caselli runs the WP Trax system shock. Caselli’s Rally machine uses a WP PDS shock that is shorter in overall travel and is by no means as technologically advanced when compared to the Trax system shock mounted on the Baja machine.

Controls: Caselli prefers Renthal grips and twin-wall 999 bars (McGrath bend) on both machines with the crossbar removed for a little additional flex. For Baja he runs a GPR stabilizer above the bar with a custom mount provided by GPR. The Rally machine is equipped with an under-the-bar-mounted Scotts stabilizer. KTM Hard Parts rubber-mounted bar clamps and Vibranators in the bars help with vibration in Baja on the sections when he is doing 100-plus mph for 10 minutes or longer. Front brake levers on both bikes are shaved down for a skinnier feel. The shift lever for both machines is custom made to clear the custom-made ignition cover. On the Baja machine, it’s modified even further, with a hammerhead +20mm tip, making the distance between footpeg and shifter the same as a stock 450SX. A new addition to the Baja machine is the oversized pegs, similar to the ones run on the Rally machine.
Brakes: KTM brakes are some of the best in the business, and on the Baja machine, the front brakes are completely stock, straight off the EXC model bike, because it has a longer line to clear the headlight. A Galfer rear brake line is used because it is thicker and more durable than stock, with a Motion Pro brake snake attached to the pedal to keep foreign objects from ripping it off. Brake pads are chamfered front and rear on the Baja machine to help with fast wheel changes during the race. The Rally machine uses the stock Brembo braking systems front and rear off the KTM 690 Enduro.
Fuel capacity: In long races such as Baja and Dakar, fuel mileage and the ability to carry enough fuel efficiently is very important. Baja is about speed; the racers pre-run their section enough times to know every inch and what is the fastest way through it. Pits are set up about every 50 miles or so to provide assistance, with fuel stops scheduled so often that Caselli’s Baja machine’s IMS tank only holds 3.1 gallons of fuel and is equipped with a quick-fill system. Dakar, on the other hand, is about navigation; the racers have not pre-run the course and are guided by a road map mounted above the handlebars. Although top speeds can reach the same heights as in Baja, they are not maintained for as long or as often. Caselli’s Rally machine has three fuel tanks: two in the front and one in the rear, with a total capacity of 9 gallons. The petcock is located above the footpeg on the right-hand side, which gives Caselli two options for fuel consumption. 1. Allows the fuel to drain equally, front and rear, to keep the machine balanced. 2. Allows him to choose whether to drain the front tank or the back tank first. Caselli says both ways have their advantages; it just depends on what type of terrain the stage consists of on that day.
Wheels: Stock KTM hubs are laced to RK Excel rims with stock spokes on both machines. KTM feels this is the strongest combination available.

TIRES:  Baja front: 80/100/21 Dunlop MX81 with bib mousse insert
Rally front: 90/90/21 Michelin Desert Race with bib mousse insert
Baja rear: 120/90/18 Dunlop MX81 with bib mousse insert
Rally rear: 130/80/18 Michelin Desert Race with bib mousse insert

Baja bike: Unlike the Rally machine, the Baja machine is a little more familiar to us. We have tested a version of the KTM 450SX similar to Caselli’s race bike in the past, or so we thought. This particular KTM 450 is one of the best off-road race machines we have thrown a leg over in a long time. The engine made smooth power off the bottom, making it easy to control on dry, hard surfaces. The midrange pulled strong but never really had a hard hit, again making it easy to control. Dirt Bike editor Mark Tilley reached 114 mph and said it felt like there was more. FMF’s factory KTM spec pipe was definitely on the loud side for our liking, but with no sound requirements down in Mexico, it’s all about making the most power possible. KTM’s hydraulic clutch has a great feel, and the action of the Rekluse Core Manual clutch never faded or faltered.
Handling on Caselli’s Baja machine was kind of a surprise. The fork was initially way stiffer than we expected and a little on the harsh side. Farther down in the stroke, the action was plush, and we never felt any sharp bottoming during hard landings or G-outs. We were completely impressed with everything the WP Trax rear shock did. The faster rebound action when the rear wheel loses contact with the ground was barely noticeable, but worked like a charm getting power to the ground. The overall comfort of Caselli’s Baja machine was another pleasant surprise. Most factory bikes we ride are set up so precise and personal to each rider, no one who rides it would like it; not the case here. For the Baja 1000, there are three other team members riding the same bike, so a neutral feel across the board is essential to success, and this bike has it.
Rally bike: Were we surprised with what this bike can do? That would be an understatement! Forget the street bike fairing and the massive appearance. You could race the KTM Rally bike on a motocross course. Imagine the looks you would get when you pull up on the line. Better yet, imagine the outrage when you pull the holeshot and disappear. The engines of the two machines are relatively the same, aside from the clutch and lowered rev limiter, but the Rally machine felt just slightly faster. Good, usable power throughout the power curve just like the Baja machine made it easy to handle the additional weight. Forks on the Rally machine are 52mm, so they are a touch larger than the 48mm versions on the Baja machine. We aren’t sure if that or the additional weight on the front end gave the forks their plush all-around feel. The WP PDS shock that handles the rear is shorter than what’s commonly found on off-road motorcycles, and it’s noticeable, but not a deal-breaker. We were still impressed by what kind of terrain the Rally could handle with relative ease. Sitting behind a fairing on an off-road bike is a little hard to get used to; we had to stand up most of the time, and in corners where sitting was required, you had to look to both sides, because there’s a blind spot directly in front of you. Despite three fuel tanks and a complete front fairing, the Rally machine was surprisingly nimble for its size. If KTM produced a production Rally machine available in the U.S., we are convinced every unit would be pre-sold.

We came away from our test session with several lessons learned. First, the bikes that Kurt races might look completely different, but inside, the cores aren’t that far apart. They share the same flawless attention to detail, the same stunning performance and the same crisp setup. The Baja bike might not have been much of a surprise, but our thoughts and conceptions about what a rally bike is and isn’t are completely shattered. The bikes that we see hauling across sand dunes and South American vistas aren’t the mammoth, ill-handling street bikes of the past by any means. They are thoroughbred racers, just like what we race on this side of the world. And, at the same time, our respect for Kurt Caselli and what he has accomplished in his career is as deep as ever.

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