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What is a 270-Degree Crankshaft Parallel Twin and Why is It So Popular?

What is a 270-Degree Crankshaft Parallel Twin and Why is It So Popular?

When it comes to automobiles, including motorcycles, engines hold a significant importance. Every time a new motorcycle is introduced in the market, the first component that attracts the most attention is the bike’s engine, and at times, many motorcycles become perpetual best-sellers because of their efficient engine configuration that imparts a unique character to the motor and ensures a smooth riding experience. Over the years, motorcycle engine technology has changed and improved a great deal, and one of the gifts of advanced motorcycle engineering is the 270-degree crankshaft parallel twin layout. But why is this engine configuration becoming exceedingly popular? This article will delve deeper into the workings of these engines and also explore the advantages that have contributed to their unparalleled popularity.

1. The 270-Degree Crankshaft Parallel Twin - Quick Background

The 270-Degree Crankshaft Parallel Twin - Quick Background
Photo Credits: Motorcycle Daily

The 270-degree crankshaft parallel-twin engine design was first introduced by Yamaha in the mid-1990s. The Japanese motorcycle manufacturer installed the 270-degree crankshaft parallel twin power plant in its TEX 850 and the TDM 850 motorcycles. By the 2010s, Yamaha had mastered the 270-degree crankshaft parallel twin with its all-new CP2 (crossplane 2) motor. The brand’s CP4 inline-four engine technology and CP2 configuration, both utilized the same working principles. Eventually, the motorcycle manufacturer also installed these refined engines in the Yamaha MT-07, the Yamaha YZF-R7, and the Yamaha Tenere 700 lineups.   

The fact that Yamaha’s 270-degree crankshaft parallel twin-powered motorcycles were getting an overwhelming response from the riders compelled other motorcycle brands to adopt a similar engine design and technology. As a result, both Triumph and BMW tweaked their 360-degree engine into 270-degree parallel twins. Moreover, other motorcycle manufacturers opted to replace their complicated V-twin engines with compact and affordable 270-degree engines that had a low production cost and were easier to package.

A similar shift was observed in KTM, Suzuki, and Honda's engine design. Almost all KTM mid-sized motorcycles, featuring V-Twin engines, now boast parallel twin engines. However, KTM has preferred a slightly larger crankshaft angle - a 285-degree crankshaft parallel twin. Similarly, Suzuki introduced its version of the 270-degree crankshaft parallel twin through its 776 cc Suzuki GSX-8S lineup. Much to the approval of many riders, Suzuki has also equipped the same engine in its middleweight adventure motorcycles - the V-Strom 800 DE and the V-Strom 800 RE. Honda has been using the 270-degree crankshaft parallel twins to power its motorcycle for many years now and this technology has now become widely common across the brand’s different lineups, including its iconic adventure motorcycle - the Africa Twin.

2. What is a 270-Degree Crankshaft Parallel Twin Engine Configuration

What is a 270-Degree Crankshaft Parallel Twin Engine Configuration
Photo Credits: Dirt Rider

You may have noticed the terms ‘powered by 180, 360, or 270-degree crankshaft’ when reading motorcycle reviews, or checking spec sheets of the latest models, but often failing to understand what it means. Any x-degree crankshaft highlights the position of the crankpins or journals connected to the rods. There are three most common configurations used in motorcycles:

  • 180-degree crankshaft parallel twin
  • 360-degree crankshaft parallel twin
  • 270-degree crankshaft parallel twin

2.1 180-Degree Crankshaft Parallel Twin

Conventionally, there is a single crankpin per cylinder. If the crankpins of a standard parallel twin crankshaft are facing opposite directions, then the engine configuration is called a 180-degree crankshaft. In such motors, there is a complete rotation of the crankshaft between each firing order of the cylinder. Moreover, the engine pistons move in opposite directions. In the 180-degree crankshaft parallel twin configuration, one piston hits the BDC, bottom dead center, while the other hits the TDC, top dead center, simultaneously, effectively neutralizing opposing forces, offering an ideal engine primary balance.

Even though the primary balance is achieved, the 180-degree crankshaft produces an undesirable rocking motion, also termed the rocking couple, and to remove this motion, counter balancers must be installed. Another disadvantage of this configuration is its inability to achieve an ideal secondary balance. Plus, these engines make very loud unpleasant noises that take away from the riding experience.

2.2 360-Degree Crankshaft Parallel Twin

In a 360-degree crankshaft parallel twin configuration, both pistons move in sync, and the engine firing order alternates between right and left cylinders. Unlike the 180-degree crankshaft, the 360-degree crankshaft eliminates the rocking couple, but on the other hand, it fails to achieve the ideal primary balance. Consequently, the 360-degree crankshaft never managed to gain the favor of the riders or manufacturers and has been jettisoned in favor of the 180-degree or 270-degree crankshaft parallel twin.

2.3 270-Degree Crankshaft Parallel Twin

In the 270-degree crankshaft parallel twin layout, the pins are positioned about 270 degrees from each other. After a single piston fire, the crankshaft rotates 270 degrees, resulting in an uneven firing order. Though the 270-degree crankshaft does not offer the perfect primary balance, it offers a perfect secondary balance, and the primary forces can be balanced by installing a balancer shaft. Moreover, compared to the 180-degree crankshaft, the 270-degree crankshaft creates a less distinct rocking couple. Furthermore, in this engine layout, the pistons are in constant motion, effectively decreasing inertia.

The 270-degree crankshaft parallel twin offers a unique character to the engine in the form of deep sound, a V-twin-like riding feel, and light vibrations that make the engine soulful. 

3. Advantages of a 270-Degree Crankshaft Parallel Twin Engine Layout

Advantages of a 270-Degree Crankshaft Parallel Twin Engine Layout
Photo Credits: Suzuki Cycles

The immense popularity of the 270-degree crankshaft parallel twin engines is a result of the many benefits this engine configuration offers. Here are some advantages of using the 270-degree crankshaft in motorcycles.

3.1 Compact Design

The 270-degree crankshaft parallel twins are popular because of their simple yet highly efficient design, which ensures a lower manufacturing cost and offers effortless packaging. Another advantage related to the compact design of this configuration is that it creates a streamlined profile of the motor, allowing motorcycle engineers to use the same engine platform in different lineups without jeopardizing stability, handling, and rider safety. The streamlined look of the engine also helps create a sleek silhouette of the bike and complements its minimal styling. 

3.2 Ease of Maintenance

The 270-degree crankshaft parallel twins feature a single-cylinder head. This spec essentially means that these engines have fewer mechanical parts; therefore, there will be less repair work, low maintenance costs, and enhanced reliability for long-distance rides.

3.3 Optimal Torque Delivery 

Through the 270-degree crankshaft parallel twin engine platform, engineers have tried to prioritize and maximize a motorcycle power plant’s torque production, especially low to mid-range torque delivery, since this range is responsible for offering responsive acceleration in different riding scenarios. Centered around this concentrated effort, the 270-degree crankshaft parallel twin allows riders to easily make quick acceleration from slow speeds, overtake other vehicles safely, and enjoy a smooth ride even on traffic-congested city streets. With its impressive torque delivery, the 270-degree crankshaft also makes sharp maneuvers and highway cruising possible. This is why any rider who prefers to cover long stretches of road at constant speed without the need for frequent gear shifts opts for the 270-degree crankshaft parallel twin.

3.4 Unmistakably Distinct Engine Sound and Personality

The 270-degree crankshaft parallel twin design offers a certain exclusivity to motorcycles that can be identified from afar. Be it the deep throaty growl of the exhaust, soulful personality of the power plant, or the feel of the vibrations produced by the 270-degree crankshaft, these parallel twins are lively and offer a dynamic performance on the road. The vibrations of the 270-degree crankshafts are also appreciated by many riders, a privilege that many other engine configurations do not enjoy.

3.5 Fit for a Broad Selection of Two-Wheelers

As discussed supra, the trim and minimalist layout of the 270-degree crankshaft parallel twin motor allows engineers to easily incorporate them in different two-wheelers. This versatility can also be seen across different motorcycle segments. The 270-degree crankshaft parallel twins do not favor a certain type of motorcycle and can be installed in sports bikes, adventure motorcycles, standard street bikes, and other motorcycle genres.

3.6 Exceptionally Fuel-Efficient Performance

Another notable benefit that has earned the 270-degree crankshaft parallel-twin immense popularity is their fuel-saving performance, especially if the motorcycle is equipped with a premium engine control unit. This management system, along with the 270-degree crankshaft format, optimizes fuel combustion by mitigating internal friction, ensuring a commendable fuel economy. For these benefits, parallel twins have also become a popular choice for many latest adventure touring motorcycles such as the Suzuki V-Strom 800 DE.

3.7 Traction

Another benefit that has made the 270-degree crankshaft parallel twins a success is their ability to mimic the levels and intensity of traction and grip of the V-twin motors. The high amounts of low-end torque produced by this engine platform increases a motorcycle’s traction and grip intensity, preventing it from skidding and making it safer in wet and off-road riding conditions.

3.8 Power Generation

The 270-degree crankshaft parallel twins are highly advantageous when it comes to yielding steady and dependable power. Hence, motorcyclists who enjoy long distance travels and use their bikes for urban commutes can easily handle their two-wheelers at higher speeds due to the expected power increases across the rev range. As a result, the 270-degree crankshaft parallel twins are not rivaled by any other motorcycle engine type, especially when an adrenaline-fueled escapade and an electrifying adventure are under question.

4. Possible Disadvantages of a 270-Degree Crankshaft Parallel Twin

The 270-degree crankshaft parallel-twin engine offers many advantages and that is why it is getting immensely popular among motorcycle manufacturing companies and riders worldwide. However, this engine configuration is anything but perfect and comes with limitations that many riders tend to dislike.

4.1 Production of Vibrations

As mentioned earlier, 270-degree crankshaft parallel twin engines tend to produce vibrations at higher rpms. It is said that these vibrations are anything but harsh and help impart a soulful character to the engine, making motorcycle riding even more exciting. However, some riders find these vibrations unpleasant and often find them to be the reason behind fatigue on long rides.

4.2 Less Production of High-End Power

270-degree crankshaft parallel twins are known for their ample low to mid-range torque production. But unfortunately, it is observed that the production of high-end power is not a strong point of these torquey motors. On the other hand, V-twin engines and inline-four engine configurations offer the best of both worlds. The limited amount of peak power production by these engines tends to affect the overall performance of the motorcycles, especially at higher rpms. Moreover, it can also limit a bike’s acceleration and top speed in demanding riding conditions. 

It is also worth mentioning that the design focus of the 270-degree crankshaft parallel-twin engine layout is to increase torque production, but this is usually achieved at the expense of a narrower powerband. Consequently, during highway travels or when traversing harsh terrains, motorcycles with these parallel twins require frequent gear shifts to prevent strain on the engine.

4.3 Lack of Perfect Primary Balance

As discussed earlier, the 270-degree crankshaft parallel twin configuration struggles to achieve the perfect primary balance. If not monitored and engineered carefully, The irregular firing intervals of this engine configuration can result in harsh vibrations if not monitored and engineered carefully, resulting in an unpleasant and tiring riding experience. 

4.4 Heat Production

The 270-degree crankshaft parallel twin power plants pose many challenges to engineers and riders in terms of excess heat production, dissipation, and management. This configuration offers a compact design, and as a result, there is less room to install large cooling systems for optimal heat dissipation. When riding for long hours, especially in hot weather and dense traffic conditions, riders may experience extra heat that can make riding unpleasant and exhausting.

4.5 Potential Maintenance Challenges

The 270-degree crankshaft parallel twins became popular especially because of their simple design. However, the distinct firing orders of these motorcycle power plants can pose some challenges for riders in terms of engine maintenance. On the other hand, many motorcycle manufacturing companies are posed with the challenge of achieving precise timing for ignition and fueling across the rev range. For this, many motorcycle brands resort to equipping the motorcycle with high–end engine management systems (EMS) that may increase the production costs, retail price, and maintenance costs. However, this point remains debatable because many riders believe that the simple layout of these parallel twins offers a significant cut in the maintenance costs.

5. Do All Motorcycle Brands Use 270-Degree Crankshaft Parallel Twin 

Do All Motorcycle Brands Use 270-Degree Crankshaft Parallel Twin
Photo Credits: Harley Davidson

While the shift towards 270-degree crankshaft parallel twin engines has almost turned into a new movement in the global motorcycle industry, many motorcycle manufacturers have yet to make the change. It seems that Ducati, Harley Davidson, and Kawasaki are inclined towards maintaining their heritage, and while they make improvements in their engine technologies from time to time, they are not ready to jettison their V-Twin engines just yet.

6. Last Words

The 270-degree crankshaft parallel twin engine format offers a convincing combination of distinct engine personality, and soul-satisfying rumble, a compact design, and highly dependable performance both on and off-road. A highly popular motorcycle engine design, this configuration deserves all the attention it has garnered over the years. Offering enhanced fuel economy, a low maintenance bill, and an interesting torquey riding experience, the 270-degree crankshaft parallel-twin engine layout is quickly becoming a staple specification in a wide range of motorcycle lineups of the most prominent global motorcycle brands. If you are someone who remains unimpressed by the performance of inline four-cylinder engines or V-twins, consider riding a bike powered by a 270-degree parallel-twin engine for an exhilarating experience. 

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