A modern box engine located on a motorcycle.

Parallel Twin Engine vs. Flat-Twin Engine: What’s the Difference?

A Comparison of the Parallel Twin Engine and the Flat-Twin Engine Inside Motorcycles

When doing research for your next motorcycle purchase, you may be curious about what engine type to focus on. As twin engines are incredibly common in the industry, there are many different variations of them. One example comes in parallel-twin or flat-twin engines. But what’s the difference? At Twisted Cycles, we compare the two powertrains below:

What is a Parallel-Twin Engine?

Widely known for being a good beginner engine, the Parallel-Twin Engine offers a straightforward powertrain that takes up little space. The engine rests in-line with the four wheels with little exposure around a rider’s feet. As its name indicates, two cylinders run in the engine and can move opposite each other or in tandem and face parallel to each other (usually straight-up-and-down). These engines typically offer reasonable horsepower and torque but can have lots of vibration due to cylinder firing. You can find this engine in many Honda, Kawasaki, Yamaha, and Triumph motorcycles.

A blue 2020 BMW 1200RT with a flat-twin engine.

Flat-Twin Engines and Their Key Difference From Parallel-Twin Engines

Aside from parallel twin engines, the Flat-Twin engine offers key differences in layout and performance. These engines oftentimes have cylinders that lay completely parallel to the ground – similar to boxer engines. With cylinders that pump in and out in sync with one another, they vibrate much less than parallel-twin engines and make for a well-balanced motorcycle. While the ‘flat-twin’ name is used, they are typically also known as Boxer Twin engines. You can find many base flat-twin engines in the BMW motorcycle lineup as well as a handful of Harley-Davidson options.

Find Various Engine Types Inside Twisted Cycles’ Motorcycle Inventory

Whether it’s a flat-twin, parallel-twin, or a straight V-twin engine, you can find a wide range of cycle powertrains at Twisted Cycles. Between our two locations, we carry a wide variety of pre-owned motorcycles ready for purchase. To find your next affordable ride, stop into our locations in Lubbock or Corinth or view our inventory completely online!


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