REAL TEST! 2010 MXA RACE TEST OF THE HUSABERG FX450:



Not fast, not powerful, not aggressive, the FX450 asks the rider to maintain momentum, and it doesn’t get in the way if he gets the FX450 rolling. It is like a mild-mannered Clark Kent (without the Superman alter ego).

Q: FIRST AND FOREMOST, IS THE 2010 FX450 BETTER THAN THE 2009 FX450?

A: Yes, with a caveat. The FX450 is a new model that didn’t exist in 2009. The previous Husaberg was the enduro-based FE450. The FX450 is designed for cross-country racing, while the FE450 was largely a woods bike.

Q: IS THE 2010 HUSABERG FX450 A MOTOCROSS BIKE?

A: No. Think of the Husaberg FX450 by using these comparisons to KTM, which owns Husaberg. KTM basically makes three categories of bikes:

   (1) EXC. The EXC enduro models are designed for woods riding and enduros.

   (2) XC. The XC cross-country bikes are for GNCC, WORCS and hare scrambles.

   (3) SXF. The SXF bikes are KTM’s full-blown motocross bikes.

In Husaberg parlance, the FE450 is the equivalent of the KTM EXC, and the FX450 is the blood brother of the XC. Husaberg does not make a comparable SXF machine. That said, the 2010 FX450 is as close as Husaberg gets to a motocross machine, and with a few tweaks, MXA was able to race the FX450 much more effectively than last year’s FE450.

Q: HOW DOES THE HUSABERG FX450 DIFFER FROM THE HUSABERG FE450?

A: There are seven very obvious changes.

(1) Gearbox. Husaberg switched to a six-speed transmission with new ratios in first, second, third, fifth and sixth gears (only fourth gear is the same as the FE450).

(2) Forks. They used stiffer 48mm WP closed-cartridge forks (basically the KTM 450XC forks, valving and spring rates).

(3) Triple clamps. There are all-new 22mm offset triple clamps (with two bolts instead of three to feed in more flex).

(4) Shock. The WP shock gets the new “big needle” and special Husaberg FX450 valving specs.

(5) Wheels. A 19-inch rear wheel and Bridgestone M59/M70 tires come standard.

(6) Handlebars. The FX450 is outfitted with Renthal oversize bars in a special Husaberg FX450 bend.

(7) ECU map. There is no lambda sensor (which means it is now an open-loop system). They also nixed the thermostat, enduro lights, odometer and spark arrestor.

Q: IS HUSABERG SWEDISH OR AUSTRIAN?

A: Shhhh. Don’t tell anybody, but the Husaberg FX450 is made by KTM. And more than that, with the exception of the plastic, frame design and engine cases, every part on the Husaberg FX450 comes from the KTM parts catalog.

Q: WHAT’S THE DEAL WITH THE UPSIDE-DOWN ENGINE?

A: If you are among the mob majority of motocrossers who tripped over themselves to get a look at the reverse-cylinder 2010 Yamaha YZ450F, then you should recognize the Husaberg’s Jens Elmwall-designed engine as the precursor to the idea of moving the rotating mass closer to the center of gravity.

With the exception of the engine cases, the engine is made up of KTM parts, but not KTM 450SXF parts. The FX450 uses the single overhead cam, rocker arm-equipped, 450XC-W engine. This SOHC engine is the replacement for KTM’s old RFS design. The single cam activates rocker arms that control four stainless steel valves.

2010 Husaberg FX450: Although the 2010 Yamaha YZ450F may have stolen some of its thunder, the Swedish-designed and Austrian-built Husaberg is incredibly creative.

Q: WHAT’S THE DIFFERENCE BETWEEN HUSABERG’S CENTRALIZATION OF MASS IDEA AND YAMAHA’S?

A: In theory, the answer is nothing; but in practice, there are major differences. Whereas Husaberg tried to move the rotating mass of the engine’s crankshaft close to the center of gravity by flipping the engine up and over, Yamaha angled its cylinder backwards to get the rotational inertia of the cams nearer to the sweet spot.

As you would expect, both ideas achieve a lighter feel in pitch, roll and yaw, but when designers take different paths to achieve the same thing, there are side effects.

Raising the crankshaft up 100mm and backwards 160mm, and putting the gearbox beneath the cylinder rather then behind it, places the rotating mass of the crankshaft closer to the bike’s center of gravity. With the rotating mass closer to the center of gravity, the torque effect on the chassis is greatly reduced. In layman’s terms, they’ve put the part of the engine that wreaks havoc on handling as close as they can to the place where it will have the least effect on handling. Simple, but clever.

The drawback is that Husaberg moved the heaviest parts of the engine upwards (and when gravity kicks in, you can feel it).

Q: CAN YOU REPROGRAM THE HUSABERG’S FUEL-INJECTION AND IGNITION MAPS?

A: Yes. The Husaberg comes with three pre-programmed maps already installed in the ECU. These can be adjusted without having to hook up any kind of reprogramming tool. The three curves are standard, soft and aggressive. The maps are activated by plugging the ECU leads into numbered ports. The standard map is unplugged; the soft powerband map is with the leads plugged into the number 1 slot; and the aggressive map is with the leads plugged into number 2.

We ran the aggressive map. There is also a $599.95 Husaberg reprogramming tool that allows you to make more adjustments. You need a laptop computer to run the software, but you don’t need a battery because the Husaberg has its own battery power. There is also a remote dial that allows you to switch between maps without having to plug and unplug wires. It retails for $49.95.

Q: HOW WAS THE JETTING?
     
A: Given the 70-degree layout of the cylinder, carburetion would have presented some serious space issues. The FX450 is fueled by a 42mm, downdraft, Keihin electronic fuel injector. It should be noted that Husaberg dropped their sophisticated closed-loop fuel-injection management system in 2010 for the basic open-loop sensor system used by Honda, Suzuki, Yamaha and Kawasaki.

   Throttle body: Keihin 42mm
   Injector: 12-hole
   Injector size: 60 microns
   Fuel pump/pressure: Electric/40 psi
   Fuel map: Adjustable (three optional maps)
   Idle: 42 clicks out
   Notes: Husaberg equips the FX450 with a programmable ignition. It can be switched between three different maps in a few minutes or totally reprogrammed with the Husaberg programming tool.

 

Handling: Sitting still the FX450 is an overweight pig, but in motion it convinces you that pigs can fly.
 
Q: IS THE 2010 FX450 FASTER THAN THE FE450?

A: Yes. The straight-thru muffler, new EFI map, lighter weight and better gear ratios produce a bike that is faster and more responsive.

Q: IS THE 2010 FX450 FASTER THAN A KX450F, CRF450, YZ450F OR 450SXF?

A: No. It’s not fast in a white-knuckle, arm-jerking, hairball way. It is pleasant, smooth and tractable. Those are code words for slow.

Q: HOW GOOD IS THE 2010 HUSABERG FX450’S POWERBAND?

A: As far as the power goes, this is a majestically usable engine. Not fast, not powerful, not aggressive. It asks the rider to maintain momentum, and it doesn’t get in the way if he gets the FX450 rolling.

It is like a mild-mannered Clark Kent (without the Superman alter ego).

The good news is that Novice and Vet riders loved the engine. They were well aware that it took its own sweet time about getting going and could have used a little extra over-rev, but when used to its fullest, it carried speed with ease. Don’t get us wrong; it didn’t make speed, it just utilized what it had to the fullest. The power delivery was dual-stage. The low-to-mid transition was leisurely, then, as the power reached the middle, it surged with its best power delivery. It goes flat at the typical 8200 rpm of most fuel-injected bikes.

The bad news is that MXA‘s Intermediate-and-up test riders wouldn’t touch the Husaberg FX450 with a ten-foot pole. They wanted more hit, more power and faster rev. The things that the Vets and Novices liked weren’t in the wheelhouse of a pro-level rider. A pro doesn’t care much about the benefits of well-modulated power.

Q: HOW DOES THE 2010 HUSABERG FX450 RUN ON THE DYNO?

A: At 50.29 horsepower and 33.05 foot-pounds of torque, the Husaberg is much better on the dyno than we expected. Although the power is softer and slower-revving, the Husaberg FX450 actually makes more power than the 2010 Honda CRF450 from 5000 rpm to 8000 rpm (then the CRF450 pips it by six-tenths of a horsepower at peak).

When you compare it to the class-leading KX450F and KTM 450SXF, the Husaberg isn’t very impressive. It gives up over 3-1/2 horsepower at peak to both the green and orange bikes (and 4-1/2 horses at 9000 rpm to the KTM 450SXF).

Q: HOW WAS THE HUSABERG FX450 SUSPENSION?

A: We don’t know. Well, we do know, but because we knew, we didn’t even try to run it. Since we were only interested in racing motocross on the 2010 FX450, and we knew that the stock forks and shock weren’t up to the task, we swapped the FX450 forks for a set of KTM 450SXF forks. This may seem like an exotic switch, but it isn’t. The stock Husaberg forks are in fact off a KTM 450XC (which has lighter valving and softer springs than the SXF forks we switched to). We could have revalved the stock FX450 forks to achieve the same setup, but it was quicker and easier for us to make a brand-to-brand swap.

As for the shock, we couldn’t make a straight-across swap from the 450SXF to the FX450. Although the Husaberg shock is a replica of the KTM 450XC shock, the piggyback reservoir is mounted slightly askew to clear some parts of the Husaberg frame?thus the KTM shock won’t fit on the Husaberg. We revalved the Husaberg shock to SXF specs and added a 7.6 kg/mm shock spring.


Optical illusion: You have to look at this engine twice before you can figure it out. The cylinder is laid down at a 70-degree angle.

Q: WHAT WAS OUR BEST FORK SETTING?
 
A: For hardcore racing, we recommend this fork setup on the 2010 Husaberg FX450:
   Spring rate: 0.50 kg/mm (0.46 stock)
   Oil height: 365cc  (380cc stock)
   Compression: 12 clicks out
   Rebound: 12 clicks out
   Fork leg height: 5mm up
   Note: By looking at the numbers, you can tell that our 450SXF forks were much stiffer than the stock FX450 forks. These are new forks for the Husaberg, but not for KTM. Thanks to new seals and bushings, the amount of stiction has been reduced. Previous WP forks had excessive static friction. If you think the forks dive too much, you can raise the fork oil height by 10cc.

Q: WHAT WAS OUR BEST SHOCK SETTING?
 
A: For hardcore racing, we recommend this shock setup for the 2010 Husaberg FX450:
   Spring rate: 7.6 kg/mm (7.2 kg/mm stock)
   Race sag: 105mm
   Hi-compression: 1-1/4 turns out (1-1/2 stock)
   Lo-compression: 12 clicks out (15 clicks stock)
   Rebound: 12 clicks out (22 clicks stock)
   Notes: We set up the FX450 with 105mm of race sag with our stiffer 7.6 kg/mm spring and SXF valving.

Q: HOW DOES THE 2010 FX450 HANDLE?

A: We absolutely loved it. Adored it! The combination of Jens Elmwall’s centralization of mass, our suspension stiffening program, the new offset, the livelier powerband and more balanced stance produced a bike that wanted to turn. No! We mean insisted on turning. The FX450 could rail berms, track through ruts and change directions on flat turns like?dare we say it?a Suzuki.

Perhaps if we had kept the ultra-soft XC forks and shock, we would have been singing a much different tune. But with our suspension setup, this thing was a dream to ride on a tight, twisty track.

We had a simple way to get the handling dialed in. We slid the forks up in the clamps until the FX450 exhibited oversteer, then we slid them down two millimeters. If the track was high-speed and rough, we slid them down further.

What we didn’t absolutely love is that the FX450 is heavy, and no amount of Elmwall legerdemain can make that extra 20 pounds disappear. It might dissolve in the air, but it returns when you land. It might vanish when you lean it into a berm, but it re-establishes itself when you straighten up. The FX450 might feel agile when pitching the nose up and down over a tabletop, but it feels portly when terra firma is under the wheels.

All that said, we were impressed.
 
Q: WHAT DID WE HATE?

A: The hate list:

(1) Subframe. From an innovation point of view, Husaberg’s monocoque plastic subframe is very trick; but on a practical level, it is stupid. It is ungainly, bulky, blocks access to the shock (we had to take the shock off the bike to change the spring preload) and, even with molded-in handholds (which are too far forward to be of any use), we’d need a Charles Atlas body building course to get the FX450 on its stand. Give us an aluminum subframe and we’ll be happy.

(2) Weight. We have a rule at MXA: If you can’t pick it up, you can’t race it. The Husaberg is on the no-fly list. For all the stuff they removed from the FE450 to make it into the FX450, you’d think it would have added up to more than a three-pound weight savings.

(3) Cost. At a startling $9498, you gotta want to be different.

(4) Gearing. When we tested the 2009 Husaberg FE450, we were shocked with how low first gear was and how short each gear was after that. The 2010 FX450 has different gear ratios, but they are equally weird. We thought about changing the 13/52 gearing, but nothing we tried worked well enough.     

Q: WHAT DID WE LIKE?

A: The like list:

(1) Airbox. The air filter is located directly behind Husaberg’s remote gas cap and uses the seat as an airbox cover. Yamaha might want to buy a Husaberg to see how easy it can be to design an accessible airbox.

(2) Seat. The seat comes off in five seconds with a ripcord-style cable release system. Unfortunately, our first FX450 seat was constantly falling off in the middle of motos. The second one stayed put.

(3) Gas tank. The 2.2-gallon gas tank is under the seat to help with the centralization dealio. It’s translucent gray and isn’t all that attractive, but we aren’t fans of black, either.

(4) Gas light. There is a low-fuel idiot light next to the EFI diagnostic light that comes on when you get down to a half gallon of gas. This is useless to a motocrosser, but we found the idea amusing.

(5) Diagnostic light. Should there be something wrong with the engine’s electronics or sensors, this light will flash out a Morse Code-style dots-and-dashes signal. For example, four long flashes and one short flash means a short circuit in the fuel pump circuitry.

(6) Steel frame. Although it is not identical to a KTM frame, the FX450 does adhere to KTM’s design philosophy.

(7) Brakes. MXA has always been impressed by KTM’s 260mm front brake, but never has a bike needed good brakes as much as the overweight FX450.

(8) Electric start. Push-button bliss.

(9) Graphics. Not being Swedish, we aren’t that into the blue and yellow decor, but we like the durability of inmold graphics. They last forever.

Q: WHAT DO WE REALLY THINK?

A: From a purist point of view, the 2010 Husaberg FX450 is too heavy, too slow and too weird to be taken seriously by hardcore racers. On the other hand, this bike is like no other machine on the planet…and because of that, it does some things remarkably well. A cross-country racer who does the occasional motocross probably couldn’t find a better bike.

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