Motorcycle Engines Part 1 – Singles, Twins and Triples

Motorcycle engines come in a number of configurations. They normally range from one cylinder to six cylinder engines, but you can also find a few exotic models with eight and even twelve cylinders. As you can imagine, the number of cylinders affects performance.

Motorcycle engines can also work on two stroke or four stroke cycles, which also plays a role in the performance of the bike, but I won’t get into that discussion in this post. I will focus in the number of pistons each engine has and their respective characteristics.

In this first part, I will talk about: one, two and three cylinder motorcycle engines. In the next one, I will talk about four and six cylinder engines.

Single Cylinder

These motorcycle engines have a single chamber with one piston. They are usually installed on off-road bikes, but you can also see them in small to medium size street motorbikes, as some Buell models, equipped with them.

Single cylinder motorcycle engines produce loads of torque at lower RPM*. The downside is that the movement of the single piston also produces a lot of vibration (as there is nothing to counterbalance the forces produced by the only piston in the engine).

Another issue to have in mind is that most of the single cylinder motorcycles are normally pretty noisy.

Twin Cylinder

Two cylinder motorcycle engines can be found in two configurations:

- V-shaped motorcycle engines, most commonly known as “V twins”

The pistons in these engines are equal in size and they are normally angled between 60 to 90 degrees. They are more powerful than single cylinder engines due to a greater displacement** and a larger quantity of fuel combusted in each stroke. V Twins can deliver a good amount of torque at low RPM.

The V shape configuration also reduces vibration as the forces produced by each piston counterbalance each other.

Probably the best known V-shaped twin engine equipped motorcycles are Harley Davidson bikes.

- Side-by-Side or opposed cylinder configuration

Normally called a ‘Boxed’ or ‘Boxer’ configuration, these motorcycle engines produce good power and torque with low vibration. Not everybody likes this configuration because the cylinders protrude out the sides. This can make cornering difficult.

Another challenge for the bikes using boxer engines is the necessity to protect the rider’s legs against the heat produced by their protuberant pistons.

Triumph has used this configuration in some of their models, but probably the brand that has mastered boxed motorcycle engines the best is BMW.

The Triple

This configuration is not very common, but three cylinder motorcycle engines have excellent power and torque. They also have good vibration characteristics. One advantage of triple cylinder engines is the ability to produce higher RPM, thus producing more power and at the same time weighing less than four cylinder motorcycle engines.

It’s not common to see a three cylinder American bike, but British and Italians have adopted this configuration for a few of their models. You can find triples in motorcycles from: Triumph, BSA and Benelli.

Well this is it for this post. Come back soon for Part II. You can also subscribe to the RSS feed or Email Updates to learn about new entries in this blog.

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Enjoy the Ride!

Rider
WorldWideMotorcycles.com

*Displacement: the total volume of air and fuel the cylinder can hold before compression occurs (source Babylon´s Glossary of Automotive Terms).

** RPM: revolutions per minute.

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