The Ultimate Off-Road Race Bike?
Story by Trevor Hunter, Photos by Trevor Hunter/Craig Hunter/John Kilmartin
After a few months of riding and racing our 2019 KTM 250 XC, courtesy of 3 Brothers KTM, we seeked to smoothen out its rough spots and fine tune its sweet spots. With what was planned as a full year of racing ahead of us in 2019 with the AMA Big6 National Grand Prix Championship Series and the AMA District 37 Sprint Enduro Series, we were looking for a capable bike to try and fit across a wider variety of terrains and races. However, with motorcycles usually comes injuries, and the injury bug caught us in the beginning of January. Therefore, almost the entire first half of the year’s races were thrown out the window and watched on the sidelines while our project bike waited gracefully. Still, we managed to squeeze in a few races so far this year with the Big6 NGPC Series and a couple local SRA GP races.
First, let’s start with some of the modifications we made to the bike. In stock trim, the 250 XC motor has quite a bit of power, and with the aggressive power valve spring installed, going fast wasn’t much of an issue. Still, we desired to alter the power characteristic a bit and transform it from a smoother powerband to a snappier, aggressive power preferred for GP racing. To accommodate this desire, we went after FMF for a Pipe/Silencer combo and also installed a Boyesen RAD Valve. FMF sent us their signature Factory Fatty pipe and paired it to a Powercore 2 silencer.
Compared to the stock system, the FMF combo was a noticeable improvement as it transitioned it from an off-road feeling motor to more of a moto style motor. Throttle response was improved and a little more crisp off the bottom. Bottom-mid power was increased as well as a slight increase on top. As good as the system was, we plan on trying a Shorty silencer to really get the bottom-mid power and aggressiveness that we’re looking for. Similarly, after installing the Boyesen RAD Valve, we didn’t notice a huge gain. Not because the Boyesen’s product is bad, but more so that KTM’s stock reed cage is really good. It looks and works almost identical to the aftermarket systems. Still, we did notice slightly better throttle response and a little extra boost off the bottom. To note, we run Maxima 927 mixed at 50:1 with 50/50 110 Sunoco race gas and 91 pump gas. Also, we run their MTL 80wt gear oil and regularly change the oil every 5-7 hours.
Onto the next step, suspension was a big issue in stock trim. Suited more for East coast GNCC style terrain, the stock settings were far too soft for the high speed GP racing seen here out West. We went to the father-son duo of Earl and Ron Shuler of ESR Suspension based out of Hesperia, CA. With quite a bit of knowledge working with WP components and primarily focusing their current work on KTM’s and Husqvarna’s, we thought we’d give them a try to see if they could remedy the stock components. From the time we first took our suspension there at the end of last August to the end of 2018, we underwent two fork setting changes and one shock setting change. Initially, the first revalve from stock was a big improvement with better bottoming and a more predictable feel. However, we still struggled to find the stiffness needed when the races were at its roughest and we’re racing at the top of our ability pushing that extra 10-15%. As a result, we continued to try different settings and, since December, we’re currently pretty happy with what we have. The fork holds up and is now riding higher in the stroke and avoids blowing through in the harsh breaking bumps. Additionally, the rear end tracks straight and soaks up everything from big whoops to small acceleration chop. In addition, ESR is a believer in the Pro Circuit Linkage System for this bike. It creates a more progressive stroke softening up the initial stroke while also helping bottoming resistance. When we put the linkage on, we did have to go up one spring rate from the stock 4.2 spring to a 4.5 spring.
With most of the big items ticked off our list, we went for our usual personal preference items. Fasst Co. Flexx Handlebars in the 12* Moto Low bend were one of the first for a little extra bump compliance. Additionally, we got our hands on their Brake Return Spring Kit for a little better feel at the pedal and to eliminate the pesky OEM spring that seemed to break all the time. Next up was a GPR Stabilizer Pro Kit featuring the stabilizer itself and the top triple clamp. This allows us to run the stabilizer under the bars without a significant rise. AME Grips are a personal favorite for the soft and sticky compound and we also installed a Motion Pro Titan Throttle Tube for better durability to avoid a simple broken throttle tube. ASV F4 Series Levers were installed to eliminate the risk of breaking a lever. Typically, aftermarket levers alter the feel of the front brake, and typically not in a good way; however, these ASV levers felt just as good, if not better, than the OEM ones maintaining a sturdy, precise feel.
IMS Core Foot Pegs offer a little better grip and durability against rocks and debris over the stock footpegs. We’re still waiting on an IMS gas tank as the 2.65 gallon stock option is too small for GP racing and the lack of a quick-fill system has cost us more times than we’d like. A P3 Carbon Skid Plate protects the undercarriage and cases and we’ve dinged it up quite a bit over the last few months of racing. A TM Designworks Slide-N-Guide Kit featuring their off-road oriented Factory Edition #2 Chain Guide was installed to replace the worn stock components. Their FE #2 Chain Guides feature a thick yet removable wear pad for better durability and have been used by the Factory KTM Off-Road teams for years.
A Bullet Proof Designs Swingarm Guard was installed to keep the chain guide tabs secure on the swingarm in the event of a rock or log smashing into the chain guide and breaking the tabs off. A Zip-Ty Racing Shark Fin is used to protect the rear rotor from trailside debris since the KTM’s don’t come stock with anything. Zip-Ty also sent us a Rear Brake Master Cylinder Reservoir Cap, Front Axle Nut, and Front Wheel Spacer Covers. The Master Cylinder Cap is cool because it requires a standard 10mm wrench instead of the larger 19mm like the OEM cap requires. Additionally, the Front Axle Nut is just a 3/8in drive insert instead of a 17mm nut. It’s flush designs eliminates the chance of a rock from rounding off the edges and makes front wheel changes a breeze.
Sunstar Sprockets provided us with their MXR1 Works Chain and Works Triplestar Aluminum Sprocket to replace the abused stock pieces. We elected to stick with the stock 14/50 gearing as the close-ratio six-speed transmission has plenty of top end speed and low end grunt for our application. Another small, yet noticeable changes was to our seat. Guts Racing sent us their Phantom Lightweight Seat Foam and more importantly their Gripper Seat Cover. The stock cover didn’t provide much traction and had us slipping and sliding coming out of corners taking a little extra energy to hold on. The Guts cover has both gripper material and ribs and offers more than enough grip. At times it can be too much, especially after a long day of riding, but they do have a standard gripper seat without the ribs. To match our RAD Valves, Boyesen sent us their new Clutch Cover. This adds both style and durability as the stock KTM cover is paper thin and prone to damage without much effort. To nail our starts, and we’ve pulled quite a few holeshots, we installed a Works Connection Pro Launch Start Device to lock the front end down and to make reaching the ground a little easier for my short legs. Polisport Plastics sent us their full orange plastic kit and the fit and finish is spot on. Megla Designs handled the appearance and we love the look of this bike.
Finally, STI Tech 2 Pro MX Tires and Nitro Mousse’s were installed. We’ve gotten a flat tire just about every time we’ve ridden this bike without mousse’s installed (on multiple sets of wheels too) so the Nitro’s were a no brainer. We’ve gotten 4 solid months of racing and riding out of the rear mousse alone and we still have some more rides left in it. The STI tires have proven to last quite a while (almost too long), but the performance isn’t far off. With years of experience on Maxxis SI Tires, we believe the Maxxis tires are better, but very marginally, than the STI tires. The 80/100-21 front tire lacks in front end traction comparison to the Maxxis, but we’re getting a 90/90-21 to test that many other riders praise over the 80/100. The rear tire works about as good as the Maxxis and durability is second-to-none.
After some racing and riding, how did this bike perform? We were able to get some race time in during the waning months of 2018 with most of this setup, but not all, and racing and riding on the full setup over the last month and a half. Coming off an injury, we only had two days on the bike, with one being mainly for photos, before lining up again at Rd. 3 of the SRA GP Series in March. In that race we finished a cautious 4th 250 Expert/10th Overall. The following weekend, we hit Rd. 4 of the AMA Big6 NGPC Series at Twentynine Palms, CA for some high speed racing action. We were running close to the Top 5 in the 1 hour 250 AA race before a costly pit stop cost us a lot of time and positions. Additionally, we finished 9th Pro 2 the following day with a few setbacks. The brutal roost 29 Palms is known for actually knocked the hydraulic clutch line lose at the master cylinder off the start and we lost use of the clutch early on on lap 1. Additionally, we stopped for a downed rider mid race costing us a few more minutes.
To get a little extra race time in, we hit the SRA GP in April and finished 1st 250 Expert. The following weekend was our final race for a bit with Rd. 5 of the AMA Big6 NGPC Series in Primm, NV. We finished a close 5th 250 AA on Saturday with a mostly trouble free race. The 1.5 hour Pro 2 race the next day started off with a big first turn crash. Additionally, an extra pit stop cost us more time and we finished 9th Pro 2.
Overall, the bike has proven to be a capable machine and the more we ride it and the more minor tweaks we make, the better it gets. A pre-season injury slowed down our progress and has us wanting more, but we’ll continue to provide updates as we continue to put hours on the bike. Until then, stay tuned to the site and to our social media outlets for more updates!
