This 400 HP Street-Legal Motorcycle Is So Powerful It Can Smoke Its Tires At 150 MPH

One of the greatest attributes of a motorcycle is its ability to do so much with so little. A bike you can buy with money obtained even just flipping burgers has enough power to outrun most cars that you’ll encounter at a red light. But is there such a thing as too much power for a motorcycle? The lucky person who buys this 400 HP supercharged Triumph Speed Triple RR from Thornton Hundred Motorcycles is probably going to find out. It’s road-legal, too, so it could be ridden on a road if you’re brave enough.

The current record holder for the world’s fastest production motorcycle is the Kawasaki Ninja H2R. That machine sports a 998cc supercharged inline-four making 300 HP and has been recorded hitting 250 mph once. Honestly, it was shocking the rider was able to overcome the drag of carrying around presumably titanic brass cojones to reach that speed.

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In theory, the mythical Marine Turbine Technologies Turbine Motorcycle (above) is even faster. The MTT Turbine Motorcycle sports a Rolls-Royce 250-C20B turboshaft engine cranking out 420 HP and has a theoretical top speed of 273 mph. I say theoretical top speed because, despite being in production for over two decades, MTT hasn’t found a rider crazy enough to ride a helicopter turbine to 273 mph.

The Triumph Speed Triple RR as modified by Thornton Hundred Motorcycles is not a production motorcycle, it’s a one-off. Once one crazy rider buys this thing, that’s it – the “production run” of exactly one motorcycle is sold out. But unlike the Ninja H2R, it’s a bike that has lights, turn signals, and a license plate. That’s right, you could ride this thing to work if you somehow manage to restrain the 400 horses in its stable. And with a top speed that’s in excess of the stock bike, you’ll arrive in record time (and with at least one police cruiser in tow, probably).

Not Your Average Bike Shop

This news comes to us from our friends at RideApart, and honestly I’m still giggling about it. This seems like one of those motorcycles that you really don’t want to try being too much of a hooligan on. Purchase of this bike should probably come with a life insurance policy and an automatic entry into the organ donor registry.

This mad machine hails from the United Kingdom from a shop known as Thornton Hundred Motorcycles. The outfit was formed in 2016 by someone named Jody Millhouse. The name of the company is supposed to be a nod to Millhouse’s home town of Thornton as well as a reference to the fabled “ton-up” era when people modified their cafe racers to exceed 100 mph.

The shop’s website says Millhouse started his custom shop at 20 years old in a disused shipping container with a bike to cut up and a maxed-out credit card. Millhouse made a name for himself early on when he rebuilt a wrecked 2017 Ducati 1299 Panigale S into a wicked streetfighter complete with an exhaust that took 70 hours to craft out of titanium. That motorcycle, shown below, had such a shocking transformation that Millhouse managed to catch Ducati’s attention with it.

Since then, Thornton Hundred has been cranking out handfuls of bespoke motorcycles. Each one is basically a one-off, featuring custom-fabricated parts from Millhouse and his team. Thornton is several steps above your common motorcycle chop shop. They aren’t just turning everyday bikes into cafe racers. Instead, Thornton extensively re-engineers these bikes and then adds in extra power. Thornton’s staff includes former MotoGP frame engineers and other crafters.

The result is that you can buy some frankly silly bikes from the firm. For example, Thornton will happily sell one of 25 of its Evo Bobbers. Now, on the surface, this just looks like your everyday Triumph bobber conversion. Then you find out that oh, this thing weighs just 374 pounds all fueled up to ride and has 120 HP on tap.

This bike is more or less the Triumph Bonneville platform re-imagined. I’ll remind you that a Bonneville weighs 520 pounds and has 79 HP, so Thornton has some huge gains here.

Millhouse has also been addicted to the idea of making the world’s fastest bikes. In 2022, his team took a Triumph Bonneville Bobber, gave it a shot of nitrous, and then put a supercharger on it for good measure. The 201 HP rocket hit 170 mph and was capable of doing a quarter mile in 10.49 seconds all while still having a license plate.

Wile E. Coyote’s Daily Driver

In 2023, Millhouse wanted to up the crazy while drawing influence from his family’s history of stunt riding. He started with a Triumph Speed Triple 1200 RR, a bike that makes 177 HP and 92 lb-ft of torque with its three-cylinder engine. Add in the low 438-pound weight and we’re talking about a really fun ride. Well, Millhouse couldn’t just leave it alone.

According to Motorcycle News, Millhouse and the Thornton Hundred team started by tearing the motorcycle’s engine down to its bare components. The engine internals were then upgraded with forged rods and pistons while the reinforced engine was capped off with a Rotrex C30 supercharger.

The motorcycle then got a new billet aluminum swingarm that stretches 180mm longer than the factory version. Millhouse engineered this swingarm to be hollow so that it could hold five liters of methanol. Those juices are ducted right into the supercharger plenum to keep things cool when the engine is pumping out 400 HP. Apparently, Millhouse spent an equivalent of $18,000 on the swingarm alone to ensure it could actually handle the power and the abuse.

Millhouse says that the supercharger and the water/methanol system can add up to 400 HP. However, the bike is currently set to deliver a mere 230 HP. The taps can definitely be cranked back up if you dare.

Making the engine stupid fast wasn’t enough, so Millhouse threw away all of the bodywork and replaced it with super lightweight carbon pieces. The Thornton Hundred team also added active aero in the form of wings connected to accelerometers and a computer. When you brake, the wings turn to act as air brakes. When you jump on the throttle, they feather out to allow for maximum speed. Apparently, the aero system can also detect when you’re turning and deploy some wing action for downforce.

It doesn’t end there, as the bike has custom brakes, carbon wheels, and, just for the right amount of silly, a chatbot. Apparently, you can play games with the chatbot and speakers on the bike will say your name when you turn it on.

Thornton Hundred says this crazy machine took seven months to build and the shop showcased it at the Goodwood Festival of Speed that year. Tuned to 400 HP, the motorcycle got so sideways it could have put a drift car to shame. Millhouse’s description of the motorcycle makes it sound almost uncontrollable. He says it makes so much power that you can basically do a burnout in any gear. A top speed isn’t quoted, but Thornton does say you can even light the rear tire up while you’re cruising in 6th gear at 150 mph.

Some of that is the power, yes. However, other assistance comes from the bike’s light 412-pound weight and the fact that the suspension is set up to put more weight up front.

Millhouse is also quick to note that all of this is still road-legal. It still has lights and a place to put mirrors. He even claims that the motorcycle will pass safety inspections and get a license plate without issue. That’s just bonkers. It’s a motorcycle that can do a burnout at 150 mph and it’s still legal for just about anyone to ride. Millhouse even managed to put 250 miles on the thing.

Expensive, And Probably Worth It

But now, Thornton Hundred Motorcycles says it’s time to say goodbye. The one-off bike is for sale right now for the price of £55,000, or $71,186. For that price, you get the bike and a two-year, unlimited-mile warranty. The shop says it’ll also ship the ride anywhere, but it’s up to you to figure out how to legally import it into your country. I could see a crafty importer figuring out a way to get this bike into America.

Amusingly enough, the price tag of $71,186 doesn’t even make the supercharged Speed Triple RR the most expensive motorcycle I’ve written about. I mean, the MTT Turbine bike costs $270,000, and remember the Curtiss “The One” I wrote about? That thing was $120,000. Dare I say, this is a better spend of your cash!

But should you be daring enough to swing a leg over this, I beg of you to wear something resembling proper gear. You’re basically strapping yourself to an ACME rocket here and unlike Wile E. Coyote, you’re not invincible. If you do buy this thing, I’m going to be seriously jealous. Just let me take it around the block; I promise I won’t hit warp speed.

Normally, crazy expensive motorcycles turn me off. I can’t imagine an instance anytime in the near future where I would see myself dropping this much money on a motorcycle. But this was a case of something so stupid and so awesome that I can’t help but love it. I’m not sure how Millhouse is going to top this, but I can’t wait to find out.