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FEATURE: The MotorbikeTimes jargon-buster glossary

We explain more than 100 biking-related terms
We explain more than 100 biking-related terms
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Wednesday, 27, Mar 2013 11:43

by Suzette Rabout and Daniel Cartwright

Do you know your EGOs from your ECUs? If researching your next bike purchase has left your drowning in a sea of acronyms and jargon, then help is at hand.

We have put our heads together in the MotorbikeTimes office to come up with the following guide to all the key terms and phrases.

Read on for our straightforward guide to unravelling biker slang, or simply click on the letter below to jump to a definition in our alphabetical list.

A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z



The Institute of Advanced Motorists


Torque expressed in degrees. Often follows a conventional tightening torque for cylinder head or main bearing fasteners


Automatic Transmission Fluid - often used in front forks

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Baby blade

400cc Honda sport bikes sold exclusively in Japan and have spawned many race series

Back marker

A slow rider who indicates the back of a pack of motorcyclists

Bar end mirrors

Mirrors that are attached to the end of the handle bars

Bar end / Weight

Handle bar extensions used to protect a motorbike if dropped


A Bluetooth intercom device fitted inside a motorcyclist's helmet

Belly pan

A small fairing position on the very bottom of a motorbike in between the front wheel and swing arm


Brake horsepower - a measure of the engines 'horsepower' without the loss of power that can come from the water pump, gearbox and other components; the term 'brake' refers to the use of a band brake to measure torque during the test


Motorcycle brakes


Short for the Honda Fireblade


A term used to describe the engine design, manufacture and both top and lower ends of the engine; it does not describe the tuning or power of the engine


Cut down cruiser-style bikes with single seats, straight handle bars and no front fairing


The diameter of a cylinder


An engine configuration in classic BMW motorbikes where the engine is mounted sideways


British Superbikes - a motosport racing series that takes place in the UK


A stunt where the back wheel of a motorbike moves faster than the front wheel causing it to lose traction and spin, leaving rubber lines on the tarmac

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An eccentrically shaped rotor that converts rotational movement into linear movement


The frame and suspension systems of a motorcycle


A cruiser style bike with large rear backrest and raised handlebars; traditionally these had the front forks extended and mounted to the frame at a more obtuse angle and no front brake

Clip on

Handle bars that each individually attach to the forks allowing them to be lowered down in relation to the seating position; these were traditionally used in race bikes

Club racing

Amateur racing series

Crash bungs

An after-market attachment that is mounted to the frame on either side of the engine to protect the bike and engine in a crash; also known as bobbins or mushrooms


Claiming Rule Team - A class of independent motorbikes that compete in the MotoGP race series


A Harley-Davidson style bike with a high capacity V-Twin engine tuned for torque


A bike that has been changed or modified to match an owner's desires and requirements

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A component used for slowing down movement in a suspension system or as a crankcase balance


Street legal motorbikes that provide different levels of off-road capabilities; they are also known as dual-purpose


Double over-head cam - an innovation in engine development where two camshafts are located within this cylinder head; this allows you to open and close valves from the timing belt below using a belt system as opposed to a push rod, and reduces valvetrain inertia

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Engine Control Unit - a component that controls the quantity of fuel injected into each cylinder


Exhaust Gas Oxygen sensor; sometimes called a Lambda sensor



The wind protection and aerodynamic shaping at the front of a motorbike


The process of changing settings on a bike to make it work; this can mean repair rather than replace

Flats / Flat bars

Straight handlebars mounted directly on to the top of the motorbike forks

Flat Spot

Occurs when the rider opens the throttle but there is a delay in the engine responding; usually caused by an incorrect fuel/air mixture

Folding the front

Causing a crash by losing traction on the front wheel of a motorbike; typically this style of crash occurs under front breaking in the apex of a corner when a bike is close to its maximum lean angle

Four stroke

An engine configuration that produces a ignition every time the crank shaft goes through two full revolutions (i.e. ignition happens every other time the piston travels down and up)

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Gas adjustable suspension

Suspension that controls different suspension settings using gas compassion rather than manual adjustments


The amount of gravitational pull simulated during a period of high acceleration or direction change

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Hanging off

Moving around the bike while cornering

High side

A motorcycle accident where the rider is thrown over the handlebars

Horse power

A form of measuring an engine's strength, see BHP

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In-line four

Describes a motorbike with an engine made of four cylinders mounted in a parallel row in the frame

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Precisely-calibrated small holes within a carburettor introducing fuel into the air stream

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Kill switch

A handlebar-mounted switch for emergency ignition cut-out; cuts the ignition circuit and prevents starter motor operation

Knee sliders

Replaceable external knee pads used to protect your knee and leathers in the event that your knee rubs on the tarmac during a race or track day


Short for Kawasaki

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Pound-force feet - an imperial unit of torque; sometimes written as ft-lbs


Pound-force inch - an imperial unit of torque, applied to components where a very low torque is required; sometimes written as in-lbs


The fitted leather suit a rider wears either on the street or the track


Light Emitting Diode - a type of light that appears on some motorcycles; they are brighter and simpler than normal bulbs and require no maintenance

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Master cylinders

The brake fluid reservoirs on the handle bars and rear sets


An outwardly tapered high-performance exhaust, shaped like a 'megaphone'


A motorbike with a single rear suspension shock absorber between the swing arm and the rear subframe


A world-class racing series that is the junior class to MotoGP; all bikes use the same 600cc four-stroke Honda engine and have a minimum bike and rider weight restriction


A world-class racing series that is the junior class to Moto2; all the competing bikes feature 250cc four-stroke engines

Muscle bike

A naked motorbike with a large capacity engine

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Naked bikes

Sport or standard bikes with minimal fairing, bodyworks and/or screen

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Off-road bikes

Motorcycles designed for off-road use, not necessarily road-legal


A term used for piston and ring size options fitted to a rebored cylinder

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Parallel twin

Describes a motorbike with a twin-cylinder engine where the cylinders are mounted in parallel to each other in the frame


The component driven down the cylinder by expanding gases


The compression the spring is under when the suspension is not subjected to any weight

Project bike

A bike that is not working and requires mechanical work to get it working; typically these are classic or desirable bikes that sit in garages unfinished for years


Pferdestärke - A German interpretation of brake horsepower

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Rat bike

A cheap old bike, typically changed from original in some way and painted black

Raised bars

Handlebars that are raised above the forks and top yolk; often used to give the rider a more upright seating position


The force with which a suspension rebounds from compression


Refers to the outer edge of a motorcycle wheel

Road racing

A professional racing series that takes placed on closed public roads.

Rotary engine

An internal combustion engine first used in Norton motorcycles that uses an isosceles triangle in a tube firing and exhaust removal system, instead of pistons, pots and valves


This abbreviated term stands for revolutions per minute; this is a measure of how fast a motor is actually spinning


A term used by bike manufactures to describe a motorbike as a Race Replica


Slang for tyres

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A term that refers to how the suspension, brakes, seating position and engine tunnng are set on a motorbike according to the rider's intended use


A bike with a two-stroke engine

Shock absorber

A damper used to control up-and-down movement of suspension or to cushion a drive train

Side car

A single wheeled cart laterally mounted to a motorbike


A term used to describe a motorbike with a single-cylinder engine configuration

Sissy bar

A backrest built onto a motorbike


The process of causing the back wheel to spin through acceleration on the exit of a corner; in a car this is called oversteer


A bike with a two-stroke engine


An acronym to describe a young maniac rider: Stupidly Quick, Underdressed and Imminently Dead


A stunt that involves lifting the back wheel of a motorbike under heavy braking

Street fighter

A sports bike that has had the front fairing removed and converted in to a naked bike; typically these have sports bike performance and the changes are purley cosmetic


A 600cc sports bike - this term can be used to describe road-legal versions of the 600cc supersport race series bikes which compete as a junior class in the WSB and BSB race series


A 1000cc sports bike - this term can be used to describe road legal versions of the 1000cc supersport race series bikes which compete as a junior class in the WSB and BSB race series

Swinging arm

Rear suspension by radius arms carrying the wheel and attached to the frame at the other end.

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Tank slapping

When a motorbike's handlebars move violently from full lock to opposite full lock; normally this occurs under acceleration


Time trials or tourist trophy


A measure of the leverage that a bike's engine can exert on the rear wheel


A term used to describe a motorbike with a two-cylinder engine

Twin shock

A motorbike with two rear shock absorbers linking the rear subframe to the either side of the rear wheel spindle

Two stroke

An engine configuration where ignition is produced in every cycle of the crank shaft (i.e. each time the piston moves down and up)

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Unsprung Weight

Anything not supported by the bike's suspension

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Vanishing point

The furthest visible point ahead; used by motorcyclists to judge the severity of a corner


Describes a motorbike with a two-cylinder engine where the cylinders are mounted at a right angle to each other (in a V-shape). This is found in many Harley-Davidson and Ducati models

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Wankel engine

An internal combustion engine first used in Norton motorcycles that uses an isosceles triangle in a tube firing and exhaust removal system, instead of pistons, pots and valves


A stunt that involves lifting the front wheel of a bike whilst travelling forward

Winter hack

A cheap bike used by a biker during the winter


World Superbike Championship - a worldwide motosport racing series



Short for Yamaha

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Have we missed anything off this list? What could we put under Q, X or Z? Let us know in the comments box below.

Comments - What do you think?

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