If you’re a hard-core sport rider and want to have some serious fun, you’ll be hard-pressed to find a more cost-effective way of getting your kicks than sliding around a go-kart track. And that’s what Husqvarna’s FS 450 is all about.

The FS 450 is a closed-course production (non-street legal), supermoto racer. Plop down $10,799, load it into the bed of your pickup, show up at the local go-kart track, and commence ripping. Aside from topping off its 1.85-gallon tank and checking pressures on the Bridgestone supermoto-specific rubber, it’s literally that easy to get a huge smile on your face.

For 2019, Husqvarna’s given it the “works” treatment with the full list of upgrades that the championship-winning Supercross platform saw. Everything from the headstock back has enjoyed a makeover, minus the knobby tires and puny front brake, of course…

The frame is more rigid and features an attractive navy blue powdercoating finish. It also includes mounting points for its accessory skid plate. It attaches to a two-piece composite subframe that’s 0.55-pound lighter.

The water-cooled 449cc engine gets an updated cylinder head design (1.1-pound lighter) that lowers the position of the camshaft. Valve timing has been tweaked to further boost the bottom-end performance—a great feature when you have Velcro traction on asphalt.

Inside the case, there’s a new Pankl-sourced five-speed transmission and a supermoto-specific Suter slipper clutch that’s actuated via a smooth-squeezing hydraulic clutch from Magura.

Husqvarna says the engine is good for 63 hp (at the crank), and it feels every bit that quick. For reference a good Supercross 450 engine puts out low 60s at the tire. Electric start means getting the engine lit is as easy as pushing a button. A lighter lithium-ion battery is also new for 2019.

Smooth off the bottom, the four-valve engine builds revs quickly with a healthy amount of midrange grunt for a 450cc single. A switch on the ProTaper handlebar allows the rider to choose from one of two engine maps. Mode 1 offers the hardest-hitting power, which we prefered, while Mode 2 is less aggressive. There’s also on/off-adjustable traction control and launch control to help you get moving from a start. We didn’t get to try the latter feature, but we hope to in a future installment.

The gear ratios complement the engine’s powerband to keep it moving forward in a hurry. There’s no speedometer, but we’d estimate a top speed of around 90 mph in top gear. Plus, its a slick shifter—an important feature when you’re constantly rowing through the gearbox at the track. On a side note, the chain adjustment slot has 5mm more adjustment range, say if you want to modify final drive gearing, or to account for chain stretch.

Aside from launches, the clutch lever doesn’t get much of a squeeze, as the slipper clutch allows you to downshift as many times as you’d like—always netting a smooth slide entering turns. The rear brake has just the right amount of feel to help engage entry slides, until you work up the speed to do it from sheer momentum.

Most air suspension typically gets a bad wrap on dirt, but on pavement it works well. The rebound circuit itself is sensitive. Adding a click or two translates into a noticeable difference in how the motorcycle responds when it hits a bump and how it goes back and rebounds through the stroke.

Physically, the motorcycle sits lower than the motocross version, after all, it trades the 21/19-inch wheel setup for a 16.5/17-inch rims from Alpina. It also has about an inch less suspension travel, front and rear. It uses slower (as compared to a dirt bike) valving that does a marvelous job of controlling suspension movement.

The air fork allows spring-rate modification (left leg) using the supplied pump and has tool-less adjusters atop the fork leg for compression and rebound damping. Both the fork and shock are sensitive to damping adjustment, with just a few clicks netting big differences in action.

Even at a quick pace, the front suspension is nearly chatter-free. It’d be worth experimenting with tire pressures, as the OE-fitted (and tubeless) Bridgestone race tires generally work better with extra heat. Make sure to invest in a quality set of tire warmers to help them arrive at operating temperature before you turn a wheel on the track.

A superbike-spec Brembo M50 Monoblock caliper pinches a 310mm wave rotor. A stout radial-mount, also from Brembo, pushes fluid through a stainless-steel line. The front brake has plenty of power but bites softly. It feels as if engineers used a less aggressive streetbike pad. A switch to a more sintered option would be one of the few changes we’d make.

Pound for pound, there isn’t a better bike for ripping around paved corners than this 227-pound (without fuel) FS 450. Sure, you can purchase a used dirt bike and install some 17s and a slipper clutch, but even after marking these modifications, you’re still not going to be even close to how well this machine performs out of the crate. If you want to get one, you’d better hurry to your local Husqvarna dealer as only around 150 motorcycles are being imported into the United States this year—approximately 50 more than this year.