Though the purpose has always been fundamentally different, several motorcycle manufacturers and/or enthusiasts have gone the other way around, building bikes with car engines.
This gave birth to some of the craziest two-wheel vehicles of all time, like the five examples featured below.
Van Veen OCR 1000
Its story started in 1974 when the Dutch company Van Veen unveiled a prototype at the Cologne motorcycle show in neighboring Germany.
Built on a bespoke frame, this wild superbike was powered by a 996 cc twin-rotor engine capable of delivering 100 hp.
The Wankel motor was initially developed for automobile use by Comotor, a joint venture between NSU and Citroen.
Plagued by reliability issues, the engine never made it into the engine bay of a passenger car, but the rights to its design were purchased by Van Veen, who adapted the twin-rotor for their wild bike.
Unfortunately, the Dutch failed to solve the engine's inherited issues, and since the bike it was mounted on had a prohibitive price tag, the company only managed to sell around 30 examples.
Boss Hoss Classic Cruser
Since 1990, Boss Hoss has produced a series of Chevy V8-powered bikes and trikes, with one of its most popular models being the Classic Cruiser.
With a ginormous 80-inch (2,032-mm) wheelbase, this is not your average Harley but an even more imposing motorcycle that you can hear from the neighboring county.
The Classic Cruser is currently available with one of three Chevy V8s. The first is an LS1 rated at 445 hp, the next is a 430-hp 383 Stroker, while the last, most potent, is a 454 small block that makes no less than 563 hp.
Besides the Classic Cruiser, Boss Hoss offers a series of models that come with one of the three abovementioned V8s.
Though calling it a motorcycle is a bit of a stretch, the four-wheeled monstrosity featured handlebars and behaved like a bike.
Unveiled at the 2003 North American International Auto Show in Detroit, the Tomahawk blew people's minds with its Dodge Viper-sourced V10 mounted on a humongous frame custom-built from solid pieces of aluminum alloy.
Rated at 500 hp, the engine was theoretically capable of launching the 1,500-pound (680 kg) "Franken-bike" to a top speed of 400 mph (643.7 kph).
However, the laws of physics won over theory during real-life tests, with experienced riders failing to reach 200-mph (320-kph) territory.
Initially a one-off, the Tomahawk was produced in 10 units, as American luxury retailer Neiman Marcus obtained the rights to develop nine non-street-legal companions to the initial concept.
Millyard Viper V10
British engineer Allen Millyard liked the idea of a V10-powered motorcycle. However, he was one of those fans who weren't sold on the futuristic four-wheel design, so he decided to build a more conventional Viper-engined bike.
Entirely custom-built by the British engineer, the insane Millyard Viper V10 looked like a conventional motorcycle - albeit a stretched one with a humongous, 500-hp 8.0-liter stuffed inside its frame.
Besides focusing on the looks, Millyard ensured his 1,322-pound (600 kg) creation was ridable and extremely fast.
In 2023, he broke the UK Timing Association (UK&ITA) two-up speed record by reaching 183.5 mph (295.31 kph) with a passenger after previously reaching 207 mph (333 kph) while riding the V10-powered bike alone.
Lazareth LM 847
Created by French coachbuilders Lazareth, which has made a name for itself for some wild builds, this so-called muscle bike featured a state-of-the-art tilting independent suspension, four-wheel-drive, and last but not least, a Maserati V8.
A 4.7-liter version of the F136 Ferrari-Maserati motor, the unit rated at 470 hp went from the engine bay of a Maserati Quattroporte straight onto the frame of this incredible machine, where it received several modifications, including a bespoke exhaust.
Despite its power, the 882-pound (500 kg) quad-weel muscle bike was limited to a top speed of only 93 mph (150 kph), presumably for safety reasons.
Like the Tomahawk, the LM 847 wasn't just a concept. It was produced in ten examples with a price tag that started at 200,000 euros (about $225,000).