From Harley-Davidsons To Moto Guzzis: New Motorcycles That Are Still Air-Cooled

Despite its legendary history in the motorcycling space, the air-cooled engine is all but extinct in a sea of modern liquid-cooled bikes. The name says it all. Air-cooled engines use ambient air as a cooling medium. As the motorcycles moves, air flows over metal fins attached to the engine's cylinder head. These fins increase the surface area of the engine head, allowing more air to pass through them and cool the engine. Air-cooled engines also use engine oil to cool the motor internally — that's why they are also called air-and-oil-cooled engines. 

Both air and liquid-cooled motorcycle engines have their pros and cons, but modern motorcycles typically use liquid-cooled motors. However, there are a few bikemakers that offer air-cooled motorcycles in their portfolios. Of course, you still have different engine formats like the parallel twin, V-twin, and Boxer-twin. Let's start with parallel twins.

A good example is the Royal Enfield Classic 650, which looks like it just rolled out of a factory in post-WWII England, and its 650cc parallel twin is just right for the occasion. This motor isn't a complex high-revving engine. It features a single overhead camshaft with an air-and-oil-cooled engine design. Giving the engine a modern twist is the 270-degree crankshaft, which enables the motor to have an offbeat pulse that makes it feel like an old V-twin rather than a buzzing parallel twin. Making an accessible 46 horsepower and 39 pound-feet of torque, the motor is less about outright performance and more about character, low-end torque, and a soulful, deep-thumping exhaust note. 

The Harley-Davidson name is synonymous with large air-cooled V-twins, and taking this legacy forward is the Milwaukee-Eight and the bikemaker's brand ambassador, the Fat Boy. Powering this massive motorcycle is the Milwaukee-Eight 117. The massive 1,923cc motor is less about its 103 horsepower and more about its crushing 126 pound-feet of torque that propels the near 700-pound motorcycle down the road with relative ease. The Milwaukee-Eight is a classic V-twin setup — its 45-degree bank angle, pushrods, and massive finned cylinders deliver the looks and soul-stirring rumble that define the American cruiser experience.

Moto Guzzi is known for dabbling with its longitudinally mounted air-cooled V-twin architecture in different motorcycle formats. The unique air-cooled V-twin sits in the V85, an adventure machine, making it a unique, charismatic, and quite engaging machine. It is an air-cooled 853cc 90-degree V-twin which has its cylinders sticking out in the breeze for optimal air cooling and is supplemented by oil jet cooling for the pistons. It's a simple motor that pushes out 80 horsepower and 61 pound-feet of torque. It's a punchy, reliable, and engaging engine with a signature rocking motion, which makes it all the more endearing and unique in a segment dominated by liquid-cooled parallel twins.

Sharing this space is the Ducati Scrambler with its 802cc Desmodue L-twin motor. This motor is the last of Ducati's iconic air-cooled L-twins. It has the bikemaker's signature Desmodromic valve system, which positively opens and closes valves, removing the need for valve springs. Delivering a punchy 73 horsepower and 48 pound-feet of torque, the Scrambler is a light, simple motorcycle with a mechanical soundtrack.

BMW Motorrad's Heritage line is the last bastion for its air-cooled Boxer twins. While the flagship GS transitioned to liquid cooling from 2013 onward, it still offers its traditional, air-cooled Boxer twin with the cool vintage-styled R 12 GS ADV. It features the venerable 1,170cc Boxer motor that delivers 109 horsepower in a characterful package. The BMW Boxer twin is legendary, but the R 18's engine is a monument in its own right. Its Boxer engine is a staggering 1,802cc hunk of metal, a throwback to the 1930s BMW R5. While the motor makes a respectable 91 horsepower, its real strength lies in its massive 120 pound-feet of torque available at just 3,000 RPM. 

The Boxer story goes beyond Bavaria as well. The Ural Gear Up is a unique fossil that's no longer built in Russia, a sidecar motorcycle with a 749cc air-cooled Boxer engine. This motor is a direct descendant of the BMW R71, famously reverse-engineered by the Soviets before World War II, to create a rugged military motorcycle. The low-compression motor only makes 41 horsepower, but its charm lies in its simplicity and reliability.

The Boxer motor sits longitudinally in the R 12 GS, the R 18, and even the Ural's frame, so every time you start it, you experience the right-to-left rocking motion associated with big longitudinally mounted motorcycle engines. It's a unique experience riding these motorcycles, as two large lumps stick out on the sides of the motorcycles. The Boxer layout allows maximum airflow around the cylinder heads and looks undeniably cool. It's the ultimate expression of air-cooled engines — huge, exposed, and mechanical.