With the 2011 Grand Prix season set to start in Bulgaria in April, the MXA wrecking crew decided to take the time to ride what may be the last of the KTM 450SXF's to race the World Championships. It is a unique bike and worth looking at.
The 2010 Grand Prix season will go down in the record books as a victory lap for Italian Antonio Cairoli and his mid-sized KTM 350SXF. With no production rule to contend with in GP racing and an enormous marketing push behind the 350SXF, Cairoli enjoyed unequaled technological assistance on his way to the 2010 FIM 450 World Championship. KTM was thrilled with the performance of Cairoli and their new baby—and the slam-dunk championship all but assured the Austrian marketers that the 350SXF would be a sales success.
But, just in case, KTM had a backup plan for 2010 in the form of German rider Max Nagl and his more traditional KTM 450SXF. It was no secret that Antonio Cairoli was enticed away from Yamaha after the Italian won the 2009 450 World Championship, while Maximilian Nagl was homegrown talent. The German had raced KTMs since arriving on the European Grand Prix scene in 2005 and had not only worked his way up through the 450 (MX1) ranks with the passing of each season, but high into the hierarchy of the Red Bull KTM factory team. Max won his first 450 GP in 2008 in Faenza, Italy, and finished sixth overall for the year. Then, in 2009, he won GPs again and ended the MX1 points chase in second overall (behind Yamaha-mounted Tony Cairoli). It could be said that Max Nagl was the star of the KTM team heading into the 2010 Grand Prix season—except that KTM hired Cairoli, which in effect demoted Nagl to second place.
Max Nagl's 450SXF was a precursor of the 2011 production bike—linkage and all.
So, when the 2010 Grand Prix season started, the eyes of the world weren’t focused on the battle between Honda, Yamaha, Suzuki, Kawasaki and KTM, but rather on the intramural duel between the heir apparent, Nagl, and the hired gun, Cairoli. Making that showdown all the more interesting was the fact that the Italian would be on a works KTM 350SXF, while the German would race the KTM 450SXF.
In a surprising start to the 2010 450 Grand Prix season, Max Nagl and his 450SXF won the opening round in Bulgaria. It wasn’t a shocking win, given that Nagl was a proven GP winner, but it did cast doubts on the untested nature of the 350SXF that Cairoli was racing. The Austrian engineers provided Cairoli with newly developed 350 engines for virtually every weekend (and without a production rule, those engines could include any technology available). Nagl, on the other hand, was working with a production engine—making his victory on the more traditional, carbureted 450 engine all the more significant.
As the season progressed, Nagl kept the pressure on, winning Bulgaria, finishing third in Italy, fifth in Holland, third in Portugal, third in Spain and third in the first moto at the USGP before getting stuck in the fencing in moto two. Only a few points behind Cairoli, Nagl was coming into the strongest part of his season when he got hurt leading into the French GP. He missed France and rode injured for the next three GPs before roaring back to score podiums in three of the last five races. In the end, Max Nagl and his KTM 450SXF ended the 2010 GP season in fourth overall—four points out of third. Cairoli stood on the top step.
So how did the MXA wrecking crew end up with Max Nagl’s works KTM 450SXF? Interesting story. KTM shipped bikes for its riders to the USA for the 2010 Motocross des Nations in Colorado. After the MXDN, Nagl’s bike was left behind at KTM’s Temecula, California, race shop where it languished in obscurity (even its MXDN German team graphics had been stripped off it).
In the past when the MXA wrecking crew wanted to test a Grand Prix bike, we had to trek to Europe to test the bike on the closest track to the factory. It is an arduous journey that doesn’t come with the benefit of testing the bike on the familiar ground that we call the “dirt dyno.” Testing bikes on race tracks that we have spun thousands of laps on allows us to tell fast from slow much easier than on some rock-hard chunk of unfamiliar Austrian earth.
Once we realized that Nagl’s bike had been left behind largely because Max will be switching to the 350SXF for the 2011 GP season, we asked KTM if they would give it to us. They hemmed and hawed but never really answered. We kept asking for Nagl’s bike, but didn’t make any headway. Then, Jody went to lunch with Roger DeCoster and asked if MXA could get Nagl’s GP bike. Roger said, “Tell me when and where and we will deliver it.” It was that easy.
SHOP TALK: DISCUSSING THE COMPONENTS
Make no mistake about it; this is a works bike. It has lots of trickery attached to and hidden inside it, but virtually every part of Max Nagl’s Grand Prix-winning KTM 450SXF could be duplicated, and many of the parts, even the exotic ones, have been offered for sale.
With the exception of a Pankl rod and piston, Max Nagl’s engine is stock—except for the works four-speed tranny.
The all-aluminum, 52mm WP forks are very soft in the first half of the stroke and over-damped in the second half.
Nagl’s bike started life as a standard showroom stock 450SXF. It uses the stock valves (from Del West), stock bore-and-stroke and stock head (although ported). The engine gets a Pankl piston and connecting rod—mainly to save weight. The cam timing is different on the intake side (because midway through the 2010 GP season Max wanted to focus the power more in the middle and less on top). Cam timing was changed by moving the cam sprocket on its tapered shaft (this could be done on a per race basis). The 41mm Keihin FCR carb is nothing special, but it isn’t the stock carb in that it uses an aluminum throttle pulley cover and shares some parts with the ATV FCR carb. The ignition is programmable via computer, but it is not the fancy GET ignitions that often grace Grand Prix works bikes. The exhaust system is from Akrapovic, but is different from the models they sell in the USA. It features a very long muffler to enable it to pass the FIM’s 115 dB two-meter-max sound test.
Internally, the transmission is a four-speed instead of a five-speed. It uses the same gear ratios as the four-speed trannies that came in the 2007 through 2009 KTM 450SXFs (but Nagl’s four-speed gearbox uses dog-style gear selectors instead of the sliding selector of the production four-speeds). Clutch action is handled by a
Brembo hydraulic actuator (as opposed to the Magura unit that comes on the production line 450SXF). The clutch itself is a Hinson unit (basket, inner hub and pressure plate) with the stock KTM primary gear reattached to the back of the basket.
KTM has the best production brakes made, including the largest front rotor. We expected Nagl’s works bike to have an even larger 270mm rotor instead of the stock 260, but the rotor size was the same (although the front and rear rotors were from Moto-Master). The Brembo calipers were stock looking, but cast out of an ultra-light material to lower the unsprung weight.
The hubs were from
Talon, with carbon fiber spools. The rims were black-anodized Excel A60s. The tires were Pirelli Mid-Soft MT32s. The front was an 80 width, while the rear was a 120. Both the front and rear wheels were outfitted with bib mousses.
It is stock. We had seen earlier GP bikes that were gusseted behind the swingarm brackets, but Nagl’s frame looked like it rolled off the Mattighofen assembly line—except for the orange paint.
With massive 52mm aluminum fork legs (the only steel parts on Nagl’s forks were the springs), Nagl’s WP SXS forks were housed in 20mm offset X-Trig triple clamps. The stock offset is 22mm, but prior to 2010, every KTM came with 20mm clamps. Apart from their massive diameter, the most notable thing about the WP forks was that they were the same forks used a few years ago with KTM’s experimental 30mm front axle. The big axle has obviously been banished, as Nagl’s bike had a 26mm axle (and there was plenty of meat left on the axle lug from where the 30mm holes used to be). KTM used to sell these forks as part of their PowerParts aftermarket lineup, but KTM only remembers selling one pair to a privateer. They still offer the smaller, 48mm-diameter version of the SXS works forks for about $2500.
Although we expected an exotic shock linkage to be hanging under Nagl’s swingarm, his bike was equipped with the stock linkage and bell cranks. His SXS shock features separate high- and low-speed adjusters and is what MXA calls the “dropout” shock (KTM now calls it the “track” system). What exactly is a dropout shock? Internally, the system is designed to speed up the rebound in order to settle faster and allow the rear tire to maintain better contact with the ground. As soon as the wheel leaves the ground, a valve opens to let the shock extend. It’s designed to work in small chop and braking bumps while compressing fully and allowing the spring to take the brunt of the impact over jumps and large hits. It is called a “dropout shock” because the rear wheel kind of drops when left dangling. The dropout aspect provides negative travel to help follow the ground. The last time we tested a dropout shock was on Mike Alessi’s 2007 KTM 450SXF (from the first time Mike was at KTM). It made a clanking sound when it moved. Nagl’s shock wasn’t as noisy. It is available through PowerParts for $1300.
Max Nagl runs a 3mm-shorter shock, which sounds like it would lower the bike, but there is a catch. The Euro-spec shock is actually longer than the American-spec shock, so Nagl’s shock, although shorter by Euro standards, is 1mm longer than the stock American shock.
Thanks to plentiful horsepower, Max Nagl’s 450SXF engine is able to
pull his tall gearing and four-speed gearbox with surprising ease. It is
a very fast motorcycle that rarely needs to be shifted.
With the help of a few key aftermarket companies, Max Nagl’s KTM 450SXF was transformed to work better for him. DT-1 handled the air filter chores, while Motorex provided the lubricants. The seat was a Selle Dalla Valle model that had been cut down and used firmer foam. It is available in the PowerParts catalog as the SXS saddle, but Nagl’s stepped version is personalized. To save weight, Nagl’s bike runs the two-pound-lighter 4.5Ah KTM PowerParts accessory battery. Renthal provides the 686 FatBars, but they are raised up 10mm on rubber-isolated PHDS bar mounts. The radiators are stockers. The gearing is 14/50—which is very tall considering that the 2009 four-speeds came with 14/52 gearing.
Perhaps the most interesting aspect of Max Nagl’s works KTM 450SXF is that KTM went to the trouble of molding the German a special one-off gas tank that uses the same shape, size and material as the stock gas tank, but has a threaded spout molded in to accept an old-school screw-on gas cap. The cap itself was the small cap that was used by KTM before they switched to the quarter-turn cap they use now.
The resonance chamber on the Akrapovic pipe has been cut at an angle to make it easier to remove the head pipe (without the chamber hitting the radiator)
TEST RIDE: HOLD ON AND PRAY
The MXA wrecking crew was excited to get a chance to test this KTM 450SXF for two reasons. First, it is the ultimate expression of what the KTM factory can do to the 450SXF. Second, it may well be the last works 450SXF available for some time—since KTM announced that it wants Nagl, Cairoli, Short and Alessi to be on 350SXFs. This could be the end for exotic KTM 450SXFs. We'll have to wait for the AMA Nationals to see what happens.
The first thing that every MXA test rider raved about was how broad and powerful Nagl’s engine was. It had grunt. Although Max gave up a considerable amount of the 450SXF’s high-rpm pull in favor of mid, that midrange was potent. The wide-ratio four-speed gearbox required a learning curve for the gun-and-run MXA test riders, but once they settled into the rhythm of maximizing the breadth of the powerband instead of its burst, they made the most of it. It was a very fast bike, and MXA test riders started to let other riders pass them on Glen Helen’s long hills just so they could blow back by them without shifting. The downside of the powerband was that the normal sensations of speed didn’t exist. The noise was lower and the acceleration was muted. It worked because it was fast—not because it felt fast.
We did have issues, largely because this was Max Nagl’s GP bike and not ours. His suspension settings were very “Euro.” His 0.44 fork springs and 5.4 shock spring are light years below the typical American settings (0.50 and 5.7). Every MXA test rider felt that the bike dropped down into its stroke and depended on damping to stop it from bottoming. This made it feel harsh. We would have preferred stiffer springs to hold the suspension higher with less midstroke harshness, but we aren’t Max Nagl. That means we don’t get to vote.
We have had good luck with Pirelli Mid-Soft tires in the past, but the mousse tubes made the tires feel strange. There was considerable roll-over, and the tires lacked the certainty of a regular tube. It turns out that mousse tubes are an acquired taste, and once a rider adapts to them, he will think that air-filled tubes are odd.
Nagl’s clutch actuation was awesome. Given that we have considerable Hinson experience, we have to give credit to the Brembo actuation system (the KTM 350SXF comes with the Brembo master cylinder stock). It was crisp and very precise. KTM also installed an X-Trig shock preload ring on Max’s WP shock. This came in handy when we adjusted the race sag. All we had to do was spin the 8mm hex head to raise or lower the spring.
CONCLUSION: WHAT DO WE REALLY THINK?
Max Nagl’s KTM 450SXF was interesting because it was a window into a different world. By no means is this bike set up for American professional motocross. The suspension is too soft for our jump-filled tracks, and the four-speed gearbox doesn’t favor an all-out frontal assault of the obstacles. It is instead a bike that is set up for the long haul. It isn’t tiring to ride. It doesn’t jerk your arms out of their sockets. It doesn’t demand constant shifting. It is almost like you are riding an automatic, because once you choose a gear, you can stay in that gear forever. On the smooth sections of the track it was a Cadillac; the handling was very good, regardless of the speed the bike was traveling. For 45-minute GP motos, this might be the ultimate scooter.
It might also be the last of its breed.
KTM Motorcycle tests