Turbo Supermoto: Turbocharged Husaberg 570!

570 ‘Berg + Boost: Alex Silversjö’s Turbo Supermoto Sleeper…  

When Cagiva purchased Husqvarna’s motorcycle division in 1987, a team of former Husky engineers decided to break out on their own, forming Husaberg in early 1988. Though the brand would only remain in existence for 25 years, Husaberg earned a reputation for producing some of the most competitive, innovative enduro and supermoto bikes in the world. In 2014, parent owner KTM merged the venerated Swedish enduro marque back into the more well-established Husqvarna brand, but ‘Bergs are still revered as legendary off-road machines.

In 2011, Husaberg introduced what would be one of its last and most coveted models, the FE 570 and its supermoto sibling, the FS 570. The machines boasted an unorthodox design. The 565.5cc single-cylinder engine was laid down nearly horizontal in the frame (70 degrees), which increased ground clearance while moving the engine’s mass and rotational inertia closer to the bike’s center of gravity. The mass-centralized design was said to make the big-bore bike much more agile and light-feeling on the track and trail.

In keeping with Husaberg’s old “Ready to Race” slogan (which KTM later took as its own), these 570 ‘Bergs were basically street-legal race bikes.

“The 2011 Husaberg FS 570 a great everyday ride. A few suspension adjustments, along with some new wheels and tires will take the FS offroad with above-average ability. Tweak the suspension a bit more, slap on a track set-up and the FS will shame many larger sportbikes. The 2011 FS can win races straight out of the crate and totally overwhelm less experienced superbike riders. The price may be premium, but the FS 570 is like buying three bikes in one.” –Motorcyclist

Enter our new buddy Alex Silversjö, a Swedish moto enthusiast whose family didn’t even have a car (just motorbikes) for the first decade of his life. Alex is a big fan of the 570 ‘Berg — “an absolute weapon on the track and the twisties.” But he says these bikes, with their fat 100mm pistons, do tend to fall a bit short at higher revs.

In October 2024, Alex crashed hard on his 2011 FS 570. While recovering from surgery, he began to see another possible advantage to the Husaberg’s 70-degree engine…

“The more I looked at the slanted frame rails in the front of the engine and started to visualize an idea. Maybe a turbo kit could be done on these bikes without destroying the supermoto silhouette… So the mission I had set out was to give the bike around 20-30 hp more while retaining reliability. Keep as much of the low end torque as possible. minimize the use of custom parts for ease of maintenance and running costs.”

Turbocharging a modern fuel-injected single-cylinder machine is no walk in the park, especially as Alex wanted to keep reliability high, costs down, and ridability a top priority. He details the home-grown setup below, which includes a Garrett GBC14-200 turbo, custom stainless header pipe, 45mm wastegate, aluminum charge pipe, 3D-printed aluminum plenum inlets, decreased compression ratio, Dynojet Power Commander 5 for tuning, and more. 

The standard bike makes 56 horsepower at the rear wheel. Running 0.6 bar (8.7 psi) of boost, Alex’s turbo ‘Berg has laid down 73 whp on the dyno — a 30% increase. However, he’s currently running 0.8 bar (11.6 psi) for an estimated ~80 whp (90-95 crank hp given a 10-15% drivetrain loss), which is serious punch for a bike that weighs just 275 lbs! For comparison, the new Ducati Hypermotard 698 Mono produces 77.5 hp and weighs 333 lbs. 

So what’s it like to ride a turbocharged supermoto that makes 20% more power and weighs nearly 60 pounds less than Ducati’s widely-heralded Hypermotard Mono? Well, Alex’s vision was to make the bike feel like it came this way from the factory, and that’s exactly what he’s done.

“Well I’m not gonna say it’s bonkers or anything… If there anything on this build that stands out for me that I’m proud of, it’s that you don’t think the bike is boosted. It feels very natural even if there is some turbo lag.”

Of course, we can’t help but wonder if Alex’s experience on these bikes has skewed his bonkers barometer — after all, a Ducati Panigale V4 R probably feels slow and sedate to Marc Márquez. We’re quite sure this turbocharged supermoto sleeper would leave quite the impression on our backsides were we able to pop over to Sweden for a test ride!

Below, you’ll find our full interview with Alex about the build, including more tech specs, photos, and riding impressions. Alex, great work on rebuilding your Berg back stronger than ever. We look forward to following along with the installation of the integrated intercooler and larger intake plenum!

Turbocharged Husaberg FS 570: Builder Interview

• Please tell us a bit about yourself, your history with motorcycles, and your workshop.

My name is Alex Silversjö. I’m 27 years old and live in a little town in Sweden right outside of Stockholm. I’ve grown up with bikes because of my father. He had an interest in them mostly as transportation, but also tinkered a little bit with them. We did not have a car in the family until I was maybe 10 years old, so cars were really odd to me as a kid.

It was somewhere around 8-9 years old where I had my first little 50cc motocross bike, and as the years progressed I started to take apart carburetors just for the fun of it. I learned stuff the hard way, most of the time. Like the good old saying: “If it ain’t broke, don’t fix it” — but as you can see on this Husaberg, that never really applied.

• What’s the make, model, and year of the donor bike?

The motorcycle is a 2011 Husaberg FS570. One of the last Husaberg-influenced bikes from the KTM family. The “FS” in the name stands for “Fyrtakts Supermotard” in Swedish, which translates to “Four stroke Supermotard.” So this bike comes exactly like this from the factory in supermoto trim. Except from one little detail…

• Why was this bike built?

Why did I want to build a turbo bike on a light supermoto platform? That idea kinda evolved on its own really. I’ve always loved the 70 degree ‘Berg for its torque and punchy mid range. It’s an absolute weapon on the track and the twisties. This 565cc single revs to 9000rpm and let me remind you that the piston is a chunky one, 100mm in diameter. But as a big thumper they tend to fall a bit short on the higher revs. So my initial thought was to maybe swap in a hotter cam.

But the more I looked at the slanted frame rails in the front of the engine and started to visualize an idea. Maybe a turbo kit could be done on these bikes without destroying the supermoto silhouette? And could I do it and still retain the feeling of a supermoto but with some extra kick to it?

 

So the mission I had set out was to give the bike around 20-30 hp more to retain reliability. Keep as much of the low end torque as possible. Minimize the use of custom parts for ease of maintenance and running costs.

• What custom work was done to the bike?

One of my goals was to minimize custom parts for ease of maintenance, but you still need to figure out some really weird stuff that never meant to work with each other.

The turbocharger is a Garrett GBC14-200, fitted to a custom stainless header pipe that also holds a 45mm wastegate. From the turbo we have an aluminium charge pipe that is really snug under the tank. I don’t actually run an intercooler on this bike…yet.

From the charge pipe to the intake plenum we have 3D printed aluminum inlets for the plenum to increase space. The plenum is actually quite small, its only 1.35L in volume, which is not ideal for a single cylinder setup, but that will get resolved together with an integrated intercooler in the future.

Engine wise its stock internals, with some small modifications that are completely reversible if need be. The obvious change is the raised cylinder to lower compression ratio from 12.2:1 to 10.5:1.

The fuel system is standard, but! I’ve bypassed the internal fuel regulator and run a 1:1 rise fuel regulator. But to make everything on the bike run as good as it does, I’ve gone with the Dynojet Power Commander 5 because it has support for setting up boost tables, which was really handy when it came to tuning.

• Any idea of horsepower, weight, and/or performance numbers?

The bike weighs 125kg. Standard this bike produced 56 whp. When boost was applied we started to see a performance gain at 0.4 bar of boost and that gave us 65whp. At 0.6 bar we got 73 whp, which is its official dyno number. But the bike is running 0.8bar of boost currently, so we should be at 80ish whp.

That’s 90-95 crank hp if we have a drivetrain loss with 10-15%. And it still runs smooth and predictable, which is a huge win in my opinion.

• Can you tell us what it’s like to ride a turbocharged supermoto?

Well I’m not gonna say it’s bonkers or anything. My vision was very clear, and I wanted to ride a bike I enjoyed and felt like it was meant to be. I’ve lent out the bike to trusted people and got these responses that I’ll never forget:

• “You have built a very strange machine.” (With a big grin on his face.)
• “If i where to pick between this turbo variant and a standard FS570, I would have gone with the turbo, even if it was more money.”
• “There is one problem…I want to buy it.”

• Was there anything done during this build that you are particularly proud of?

If there anything on this build that stands out for me that I’m proud of, it’s that you don’t think the bike is boosted. It feels very natural even if there is some turbo lag. The 3D-printed aluminium inlets are also a real cool part on the bike. Shame you don’t see them really.

But I’m proud of anything at this point. I crashed the bike pretty hard in October 2024 and started the turbo build after surgery and got help from my mates Rasmus and Casper. I also would like to thank everyone involved making this bike come to life.

Follow the Builder

Instagram: @alex_silversjo
YouTube: @silversjo