The Pros And Cons Of Every Motorcycle Engine Type


At the heart of every motorcycle is its engine, and with the bewildering variety of motorcycles we have, there are a bewildering number of engine types to choose from. In this article, we will try and explain what the pros and cons are of each motorcycle engine type. We’ve restricted ourselves to a list that looks at the most used layouts for motorcycles, which is why we have had to leave out some fascinating ones like electric motors, Wankel engines, turbines, and the V5 layout.




We’re also not going to delve into the two-stroke vs four-stroke debate, spark ignition vs compression ignition, and forced induction, whether turbocharger or supercharger. These are all discussions for another time. To get back to the topic at hand, sometimes an engine layout is the best fit for the purpose. Other times, there are a lot of different layouts chosen by manufacturers for the same purpose, which makes it very interesting for a potential customer. Here then, are the pros and cons of the most common motorcycle engine types you’ll come across.

The data used to compile this article was sourced from various manufacturers, and other authoritative sources such as Motorcycle.com and Cycleworld.com.


10 Single-Cylinder

A Dakar Rally motorcycle jumping


The most prolific motorcycle engine type in the world – but not in the US market. The low cost of this engine layout makes it ideal for much of the world, where a two-wheeler is everything from personal transport to a goods carrier. Four-stroke singles don’t rev very quickly, since they generate power every other revolution, so they need a heavy flywheel to keep the momentum of the crank and piston going.


This is also part of the reason why they are very good at torque for their displacement. The US market is used to seeing singles of the two-stroke variety on dirt bikes and enduro machines, picked for their light weight. Another downside of a single is that they don’t generate as much power for their displacement as do multicylinder machines – but some can surprise you!

Motorcycles that use this engine type:

9 Parallel-Twin

2024 KTM 790 DUKE front 3/4 action shot
Rudi Schedl via KTM


The twin-cylinder engine is the most common engine type in the US market for multiple reasons. It is a good mixture of power output and lightweight. Depending on the layout and firing order, you can choose a better torque spread or a higher power output. We will go through a few twin-cylinder layouts, and here is the first: the parallel-twin. You’ll see it in examples like the Triumph Bonneville and BMW F850 GS.


There have been quite a few parallel-twin British icons as well, although they had a 360-degree firing order, meaning both cylinders fired at the same time. A parallel-twin offers the convenience of a single cylinder head, which brings complexity down and therefore cost, and makes maintenance easier. A downside of the parallel-twin is that the engine is wide, which means more weight for the engine and thus more weight for the chassis – a stronger chassis is required to support it. This ultimately brings performance down in all areas.

Motorcycles that use this engine type:

8 V-Twin

2024 Harley-Davidson CVO Road Glide STO Engine
Harley-Davidson


The most recognizable layout of the twin-cylinder engine is a narrow-angle V twin (bank angle less than 90 degrees). In fact, it is the most recognizable sound you’ll hear, too – the ‘potato potato’ idle of a Harley-Davidson is the sound of a long-stroke V-twin idling. The primary advantage of a V-twin over a parallel-twin engine is that it is narrower, which makes for a more manageable motorcycle simply because the rider doesn’t have to splay his/her legs to have the feet touch the ground. Having one cylinder pointing towards the front also lowers the center of gravity, and the fact that both conrods can mount onto a single crankpin gives it advantages.


However, servicing them becomes complex because there are two heads, and the rear cylinder often heats up the rider in unwanted areas simply because of its positioning. Notable motorcycles with V-twin engines include pretty much every American cruiser; the KTM RC8, Aprilia RSV Mille, and the Vincent Black Shadow. Two V twin engines worth noting are a 500 cc Moto Guzzi engine from 1934 and the engine from the Zundapp KS 750, for using a V twin with an angle greater than 90 degrees.

Motorcycles that use this engine type:

Related
5 Great New Parallel Twins (And 5 New V-Twins That Are Better)

The battle of the twins

7 L-Twin

2007 Ducati 1098 Engine
Ducati 1098 engine


This configuration is called ‘L’ because it features two cylinders with a 90-degree angle in between the banks, which makes it look more like an L rather than a V. There are a surprising number of motorcycles that use the L-twin configuration, because if done right, the perfect primary balance can be achieved. The most famous manufacturer with the L-twin engine is, of course, Ducati, which has always had most of its range powered by 90-degree twins, but all of Moto Guzzi’s current engines are also L twins, although mounted longitudinally.


The longitudinal mounting takes care of packaging, since the length of the engine isn’t a problem. It also allows the engine to be air-cooled, since there is no rear cylinder hidden away out of the airflow. However, there is a slight rocking motion that occurs when you rev a Guzzi engine, just like that on an old muscle car! A downside of the L-twin is that, because of the firing order, there are vibrations, especially at high revs.


Among other notable motorcycles with this configuration are the Honda VTR1000 Firestorm, the Bimota range from the previous generation, and most of Suzuki’s V-Strom range. An interesting point to note is that although the Ducati Supermono was a single-cylinder motorcycle, it had an L-twin layout with a dummy piston/conrod setup to help it achieve the balance necessary for the high revs it achieved at its displacement.

Motorcycles that use this engine type:

  • Honda VTR1000 Firestorm
  • Suzuki V-Strom 1000
  • Moto Guzzi V8

6 Boxer-Twin Engine

BMW R18 engine
BMW R18 boxer engine


There’s only one manufacturer that has stuck with the 180-degree configuration, and if you’re here reading this, you probably know which manufacturer it is: BMW. A quick note about the difference between a boxer and a flat engine before we continue; a flat engine uses a single crankpin to mount both conrods, much like V twin engines, whereas a Boxer twin uses different crankpins and the pistons move outward and inward at exactly the same time, while using an even 180-degree firing order.


This boxer configuration is what gives BMWs the smoothness we’ve come to expect from them. The layout offers the advantage of a really low center of gravity, which aids balance and confidence, especially when lifting the motorcycle if it falls. Until recently, air cooling was enough for this layout, which means reduced cost and complexity as well – something that Ural uses to its advantage. Surprisingly, there are flat/boxer twins in the history of quite a few brands, including Brough, Matchless, Indian, and Harley-Davidson. The downside of a boxer engine? The cylinder heads are in the way if the bike falls, and on a hot day, your feet won’t appreciate being that close to the hottest part of the motorcycle!

Motorcycles that use this engine type:

  • BMW R1250 GS
  • BMW R18
  • BMW R nineT

5 Inline-Three

Triumph Rocket 3 engine close-up
Triumph


Like the previous layout, one manufacturer comes to mind immediately when an inline three-cylinder engine layout is mentioned – Triumph. In fact, the largest displacement production motorcycle engine is the 2.5-liter triple in the Rocket 3. Three-cylinder engines are more compact than four-bangers, and they generate more torque for the displacement – ideal for most real-world applications. However, since there are three cylinders, there is an imbalance since the pistons’ motion isn’t in sync with each other. This requires either power-sapping balancer shafts or counterbalancing weights on the crank, which increase the crank inertia.


Triumph has taken this imbalance further with their new generation of engines by changing the firing order to their version of the ‘big bang’ firing order, which makes them sound almost like a twin-cylinder at low revs. The advantage is a wider torque spread, but vibrations increase. There can’t be too many cons when the Moto2 engine is an inline three-cylinder engine, and it consistently breaks records that the previous four cylinders had set!

Motorcycles that use this engine type:

  • The entire Moto2 grid
  • Triumph Street Triple
  • Triumph Rocket lll

Related
10 Most Powerful Three-Cylinder Motorcycles Ever

These three-cylinder engines prove that three isn’t always a crowd.

4 Inline-Four


The other most recognizable layout other than the V-twin, the inline-four layout, is possibly the most popular layout in the history of the automobile. It has a great primary balance, but the secondary balance isn’t good, which is why it cannot be of very large displacement. However, that isn’t a concern for motorcycles, since they rarely go over 1,300 cc.


Inline fours are relatively inexpensive to manufacture because of the single head, and generate a good balance of power and torque. The downside is the engine width, the center of gravity is relatively higher than the alternative designs, and the swingarm is shorter for the same wheelbase when compared to a V4. Still, that hasn’t stopped manufacturers from turbocharging and supercharging their inline-fours to eye-popping stats – an overwhelming majority of the fastest production motorcycles all use this layout.

Motorcycles that use this engine type:

3 V-Four

Ducati V4 Granturismo
Ducati 


An alternative to the inline-four, it has many of the same advantages and disadvantages of the V-twin engine. Advantages include less width and the ability to accommodate a longer swingarm for the same wheelbase as an inline-four engine (more stability as well as the ability to put the power down better), and disadvantages include the complexity of needing two cylinder heads, two manifolds, and cooling of the rear bank necessitates liquid cooling.


The V4 layout has been around for a while – the 1931 Matchless Silver Hawk had one, and today Yamaha is the only manufacturer in MotoGP that does not use this configuration. Special mention must be made of the Honda VFR1200F, which also used a V4 engine but in a very different way; the outer cylinders were both banked forward, while the inner two cylinders were banked rearward to provide the rider with a slimmer motorcycle.

Motorcycles that use this engine type:

  • Almost the entire MotoGP grid
  • Honda VFR1200F
  • Ducati Panigale V4

2 Inline-Six

BMW K 1600 GT side right shot
BMW


You might be forgiven for assuming that the I6 was the prerogative of BMW cars and Japanese sports cars of the ‘90s. In fact, the first production six-cylinder motorcycle was an Italian motorcycle with a Japanese-derived heart. The Benelli 750 Sei showed the world what was possible with an I6 and two wheels in 1973. Others followed, but only one remains, the BMW K1600 with its curiously canted engine.


BMW claims that it is not wider than a regular inline-four – which brings us to the disadvantages of this layout for a motorcycle. It is too wide, too heavy, and the fuel efficiency would be abysmal. However, you wouldn’t find a smoother engine if you tried, and the howl from a straight-piped I6 motorcycle reminds us of the glory days of F1 when the engines had 12 or 10 cylinders, and you could hear them shriek from miles away.

Motorcycles that use this engine type:

  • Benelli 750 Sei
  • BMW K1600
  • Suzuki Stratosphere concept

Related
10 Awesome Four Cylinder Motorcycles

Older than you think, the four-cylinder motorcycle engine has a distinguished and varied history

1 Flat-Six

2021 Honda Gold Wing Tour DCT Engine
Honda


There is only one motorcycle that has used, and continues to use, a flat-six engine, and that is the Honda Gold Wing, since its fourth generation in 1987. While the cylinder banks are at 180-degrees, just like BMW motorcycle engines, it isn’t a boxer engine. This is a flat engine, which means that the opposing cylinders are mounted onto a common crankpin like V-twin engines. This allows the motor to be really short, and the flat configuration means the center of gravity is really low.


The many cylinders mean that the weight is quite high, but in the case of a full-size tourer like the Gold Wing, low weight isn’t a big target, and neither is fuel efficiency. Tank range can be taken care of with a larger fuel tank in a tourer of this size as well. Despite all the drawbacks, you’ll be hard-pressed to find a smoother engine with a wider torque band than the flat-six in the Gold Wing.

Motorcycles that use this engine type:

  • Honda Gold Wing
  • Honda Valkyrie



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