Have you ever heard the terms “V-Twin”, “Inline 4”, or “Boxer” and wondered what they mean? In this article, we’ll break down several different engine configurations, how to identify what engine a bike has, what different engines sound like, and the various nicknames for each.
Typically, the number in the name is pretty straightforward and represents how many cylinders the engine has. For example, a V-Twin has two cylinders, whereas a V-4 has four cylinders. Although there are exceptions, a reliable way to tell how many cylinders a motor has is to count the number of head pipes. It’s important to ensure you’re looking at the head pipes themselves, and not the mufflers. This is because many setups funnel the head pipes into a lesser number of mufflers, which would not accurately reflect the number of cylinders. An example would be a 6-into-2 exhaust system, which is comprised of six head pipes funneled into two mufflers. Another way to identify the number of cylinders is to count the number of spark plugs or spark plug wires.
So what does the rest of the engine name mean? The portion of an engine name that does not designate how many cylinders it has represents the orientation of the cylinders, as we’ll detail below.
Single
A single, such as the Gilera pictured above, signifies one cylinder and is a relatively basic setup. There is no need to designate its orientation to other cylinders because there is only one, hence the common nickname “One-Lunger”. All modern motocross bikes are singles.
A single represents the number of cylinders, not the engine cycle. Therefore, there are single engines that are either two- or four-stroke.
Examples: Honda CRF450, Gilera 106SS, Yamaha TT500
TWO STROKE
Sound: Bzzzz. Two-strokes are often described as sounding like a swarm of bees. Their distinct “brrraaaapp” comes from the nature of the 2-stroke engine cycle, which fires every revolution.
FOUR STROKE
Sound: Similar to a riding lawn mower. Because these only fire every other revolution, you can hear each time the cylinder fires a distinct “thump, thump, thump” which has earned them the nickname of “Thumpers”.
Unclear on the differences between a two and four stroke? Click here for our breakdown.
V’s
The name itself helps visualize how the cylinders are positioned, which is in the shape of the letter “V”. These motors are most often oriented in the frame so that one or more cylinders face the front tire and one or more cylinders face the rear tire. The “V” configuration is one of the most common modern engine styles. All Harley-Davidson Big Twin and Sportster models are V-Twins. Although rare in the world of motorcycles, “V” motors with more than two cylinders are common engines for automobiles, such as a V6 or V8.
Examples: Harley-Davidson Road King, Honda VFR, Indian Chief
V-TWIN
Sound: These engines have an iconic, throaty growl with occasional pops. Some describe it as a “potato, potato, potato” sound.
Parallel, Straight, Inline
As the name suggests, the cylinders are in a straight line, or parallel to one another. Most of these motors are oriented in the frame in a way that designates a “left” and “right” cylinder. Inline-4 cylinders are a favorite here at the shop. Most modern sport bikes use inline 4-cylinder motors, which deliver high horsepower in a small package with the capability to rev much higher than most other engine types. These engines are known for their reliability and smoother experience for the rider with minimal vibration.
Examples: Honda CBR1000, Triumph Trident, Yamaha R6
Sound: Smooth and fast, like the wings of a hummingbird.
Opposed, Boxer, Pan
With opposed motors, the cylinders jut out opposite one another, with the pistons in opposing, horizontal positions. This creates a shorter motor height and allows for a lower center of gravity, making the bike feel lighter and easier to handle than comparable-size models with different motor configurations. Due to their layout, these are always mounted in a position that has “left” and “right” cylinder positions.
Examples: Honda Goldwing, BMW R1100RT, Ural
Sound: High degree of variability based on the number of cylinders. Motors with six cylinders (like the new Goldwing’s) sound like spaceships. Motors with two cylinders (such as an older BMW) sound like a high-revving mower.
Twingle
Twingle means “twin single” and this design is unique because there are two pistons operating within the same combustion chamber. On both upward and downward movements, the pistons are in slightly staggered height positions. This is an extremely rare motor type.
Example: Sears Allstate 175
Read more about our work on the Sears Allstate here.
As you now know, there are several simple ways that you can tell what type of engine a bike has. The name, the number of head pipes, and the sound all give clues to help you confidently and correctly identify a motor.
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