Husaberg FX450 | The Unexpected Masterpiece Nobody Saw Coming

Ajouté : 2026-05-14

[00:00:00]Every MX manufacturer tilted their cylinder forward a little. Honda, Yamaha, KTM, maybe 15-20 degrees.

[00:00:06]Husaberg built a motocross machine and went 70. The FX 450 is the bike that never should have existed. Husaberg was an Enduro company, small, Swedish-born, KTM-owned, and built around four-stroke thumpers for technical off-road racing.

[00:00:19]But in 2010, they took their most radical engineering decision, a 70-degree tilted cylinder, and dropped it into the most aggressive MX-oriented chassis they'd ever built. The result was the closest thing to a motocross bike Husaberg ever produced, and it carried an engine architecture that no pure MX manufacturer had the nerve to touch. Husaberg never built a direct SXF or YZF competitor. The FX 450 was positioned as a cross-country and hare scramble machine. Think KTM XC territory, not SXF. But with a 19-in rear wheel, close-ratio six-speed gearbox, stiffened suspension, and MX-oriented geometry, it was as deep into motocross as Husaberg ever went.

[00:00:57]MXA raced it at the track, ran suspension settings against SXF specs, and dyno'd it against CRF450s and KX450Fs.

[00:01:06]This was not an Enduro bike with knobbies. It was built to gate drop. The engine underneath all of that was the same 70-degree tilted single that debuted on the FE Enduro models in 2009, designed by Jens Elmwall, built around KTM's SOHC 450 XC-W architecture, and packaged in a way no Japanese manufacturer had attempted on a competition machine. Why tilt the cylinder at all? The MX argument. On a motocross track, direction changes are violent and constant. You're loading and unloading the chassis through berms, scrubbing jumps, pivot turning in ruts, and throwing the bike around under heavy braking. Every time you do any of that, the spinning crankshaft is fighting you.

[00:01:43]A crankshaft is a gyroscope. The further it sits from the bike's center of gravity, the more leverage it has to resist direction changes and load the chassis during pitch and roll transitions. On a conventional MX engine, the crank sits low and relatively forward in the chassis.

[00:01:56]That's fine for straight-line stability.

[00:01:58]It's a problem when you need to flick a 110 kilo machine sideways at 60 km an hour. The Husaberg's answer was to move the crank closer to the point where its gyroscopic effect had the least leverage, and the 70° tilt was how they got it there. What the tilt actually did to the crank. Tilting the cylinder 70° forward moved the crankshaft more than 100 mm higher in the chassis and approximately 160 mm further rearward compared to a conventional engine layout. That repositioned the crank's rotating mass significantly closer to the bike's overall center of gravity, the neutral pivot point between the axles. With the crank sitting closer to that point, its gyroscopic forces had far less leverage on the chassis during direction changes. The bike resisted flicking less. It pivoted more neutrally. In motocross terms, a discipline where you're constantly asking the chassis to change direction quickly, that's a meaningful mechanical advantage. This is also why MXA pointed to the FX 450 as the direct precursor to the 2010 Yamaha YZ450F's reverse cylinder layout. Yamaha moved their cylinder rearward to achieve similar mass centralization goals through a different method. Husaberg had already been running the concept in production on a competitive machine before Yamaha's reverse engine made the cover of every moto magazine on the planet. The engine, what's actually in there? The FX 450 does not use the KTM 450 SXF engine.

[00:03:19]That's a common assumption and it's wrong. It runs the SOHC rocker arm equipped 450 XCW KTM's replacement for the old RFS design. Single overhead cam, four valves, rocker arm actuation.

[00:03:32]Compression ratio is 11.8 to 1, mild for a competition 450. Bore is 95 mm, stroke is 63.4 mm, displacement is 449.3.

[00:03:43]It makes 50.29 horsepower and 33.05 lb feet of torque at the wheel, more than a 2010 CRF450 from 5,000 to 8,000 revolutions per minute, but down against the KX450F and 450SXF at peak. The power character is broad and progressive rather than sharp and peaky. The engine cases are unique to Husaberg. Everything else, transmission gears, cylinder, head, crank, piston, counter balancer, clutch, brakes, radiators, electric starter, comes directly from the KTM parts catalog. This matters for renters.

[00:04:16]Sourcing parts is straightforward because you're largely working with KTM components.

[00:04:21]Fueling, EFI and the 70° problem solved.

[00:04:24]The upward facing intake port that the 70° layout creates raises an obvious fueling question. A carb mounted flat on its back has real problems with float bowl orientation and fuel level consistency, especially as terrain angle changes. Husaberg solved this with EFI from the start. Keihin 42 mm throttle body, 12-hole injector, 60 micron injector size, electric fuel pump running at 40 lb per square inch. The FX 450 runs an open loop system, simpler than the closed loop setup on the FE Enduro models, consistent with what Honda, Kawasaki, and Yamaha were running on their MX bikes at the time. Three selectable fuel maps are available and Husaberg offered a reprogramming tool for deeper ECU adjustments.

[00:05:05]The short direct intake runner from airbox to throttle body, made possible by the upward facing port, gives the FX 450 a clean unobstructed air path that conventional packaging compromises.

[00:05:16]Suspension, where it differs from the FE. The FX 450 runs stiffer MX spec suspension compared to the Enduro FE models. Up front, 48 mm WP closed cartridge forks pulled directly from the KTM 450XC spec, stiffer valving, stiffer spring than the FE's Enduro tuned setup.

[00:05:35]Triple clamps are all new with 22 mm of offset and a two-bolt design engineered to allow more chassis flex. The rear gets a WP shock with the big needle and FX 450 specific valving. MXA's race settings give you a working baseline.

[00:05:50]Front spring at 0.50 kg per mm, oil height at 365 cubic centimeters, compression 12 clicks out, rebound 12 clicks out, fork leg height 5 mm up. For the shock, 7.6 kg per mm spring, 105 mm race sag, high compression 1.25 turns out, low compression 12 clicks, rebound 12 clicks. Stock settings are noticeably softer than this. If you're planning to race, start with these numbers and work from there rather than chasing the stock setup around a track. One handling characteristic to know going in, the front end can feel slightly light in certain conditions, particularly in fast, open terrain. This is a known quirk of the mass centralization approach. More weight riding higher and further back shifts the front to rear balance compared to a conventional layout. Dialing front compression and sag properly makes a decisive difference. Riders who went through the setup process properly reported precise, nimble handling that felt closer to a 250F than a 450 in terms of how the bike pivoted. Gearbox and gearing. The FX 450 runs a six-speed close ratio gearbox.

[00:06:53]The ratios in first, second, third, fifth, and sixth are all unique to the FX. Only fourth gear carries over from the FE 450 Enduro. Close ratio means the gaps between gears are tighter, keeping the engine in its power band more consistently. For hair scramble racing on varied terrain, it works well. For pure MX, where you often spend most of a moto in two or three gears, having six tight ratios available gives you more options to match engine speed to track sections. It's not a traditional MX gearbox, but on a machine with a broad, progressive power band rather than a sharp hit, it suits the engine character. The rear wheel is 19-in MX spec. This alone is a significant distinction from the Enduro FE models running an 18-in rear. Tire selection, sidewall height, and how the bike feels through acceleration bumps and jump landings all change with that extra inch. Bridgestone M59s and M70s came stock. What riding it actually felt like. Every test rider who put time on the FX 450 said the same thing. It felt lighter than it had any right to. The mass centralization from the 70-degree layout changed how that weight felt in motion. The bike pivoted readily.

[00:07:58]Direction changes that would feel labored on a heavy conventional 450 came more naturally on the FX. MXA's verdict after their full race setup, the bike wanted to turn. In their words, it insisted on turning. It could rail berms, track through ruts, and change direction on flat turns in a way that surprised everyone who tested it. It didn't have the sharp aggressive hit of a 450 SXF or a YZF. The power was there, but it came in a long rolling wave rather than a punch. For hare scramble and cross-country racing, that's a significant advantage over a full lap.

[00:08:30]For head-to-head MX racing against bikes with 3.5 more peak horsepower, you were giving something up on the straights.

[00:08:36]The handlebar feel was specific. Renthal oversized bars in a bend developed specifically for the FX 450, combined with the two-bolt triple clamp flex geometry, gave the front end a particular compliance character. Riders coming from stiff direct feel MX bikes sometimes found the front felt less connected initially.

[00:08:54]What felt like vagueness was actually the chassis working as designed, absorbing input rather than transmitting it. Once riders recalibrated their reference points, the front end reported as precise under load. Why it mattered beyond Husaberg. The FX 450 arrived in 2010. The same year Yamaha's reverse cylinder YZ 450F generated more industry attention than any other MX bike. Both machines were chasing the same physics.

[00:09:18]Get the rotating mass of the crankshaft closer to the bike's center of gravity and reduce its gyroscopic leverage on the chassis. Yamaha moved the cylinder rearward inside a conventional engine orientation. Husaberg tilted the whole thing 70 degrees and repositioned the crank upward and rearward simultaneously. Different approaches, same problem, same solution. The difference was scale and commitment.

[00:09:39]Yamaha put their concept into the highest profile MX racing program on the planet. Husaberg put theirs into a niche cross-country machine with limited American distribution. The FX 450 ran three model years, 2010 and 2011 in the US market, with the 70° four-strokes continuing through 2012 in Europe. By 2013, when KTM retooled their engine platform with diecast cases and revised internals, the decision was made not to implement the 70° layout on the new architecture. The 2013 and 2014 Husaberg four-strokes returned to a conventional cylinder orientation, essentially KTM machines with Husaberg plastics. The brand ran its final year in 2014 before being absorbed into the Husqvarna line.

[00:10:21]The FX 450 had a limited production window, restricted global distribution, and never made it into a factory race program. It is, by any commercial measure, a footnote. By any engineering measure, it was a production motocross machine running mass centralization principles that the rest of the industry spent the next decade trying to solve through other means. Husaberg put their most radical engine into their most aggressive machine and raced it before anyone else was having that conversation. Triumph took a completely different approach. They didn't try to out-engineer anyone. They out-strategized the entire industry. How a 70-year-old British brand walked into modern motocross and immediately became a threat is a story worth understanding.

[00:11:00]That's the next video.