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Motorcyclist's Glossary


To some, motorcyclists sound like they are speaking a second language. Fact is, it's just the names and terms that have evolved over the years to describe the sport of motorcycling. Here's a quick primer.

ABS — Antilock Brake System. A component added to the braking system that detects wheel lock up. The system then modulates the brakes at that point with the idea of stopping you faster than you could yourself.

Aftermarket — Any items or accessories you buy that are not from the Original Equipment Manufacturer.

Apex — The middle or center point of a turn.

Anti-Dive system — A front-end suspension component that reduces how much the forks compress under braking, popular in the late 1980s, but seldom used now.

Bagger — A motorcycle with touring accessories like saddlebags, top box, a trunk, etc.

Boxer Twin — A horizontal engine configuration with the two pistons opposing each other, commonly found on BMW twin-cylinder motorcycles. The term comes from the resemblance of fists coming towards each other.

Brake Horsepower (BHP) — Although theoretically equal to standard horsepower, "brake" horsepower specifies that a specific engineering process was used to arrive at that horsepower number. (See also: Horsepower and Torque)

Cam — A metal shaft with oval "lobes" that rotates to open the valves in a four-stroke engine.

Carburetor — A mechanical device found on the intake side of the engine which mixes fuel and air to create the volatile mixture that gets ignited in the engine.

Chopper — Originally, a motorcycle that has had all non-essential parts removed (or "chopped") to make it lighter and faster. Today, this name generally applies to custom built motorcycles that may have a rigid frame (no rear suspension), an extended fork, and a stretched or elongated appearance.

Clip-ons — Handlebars that are clamped around the top of the fork tubes, rather than bolted to the top triple-tree. This lowers a rider's upper body on the front of the motorcycle for a racier body position.

Counterbalancer — A weight in the engine that spins with the rpm to smooth out engine vibrations.

Countersteering — The input a motorcyclist gives to the handlebars in order to steer: push the right handlebar to go right, or push the left handlebar to go left.

CruiserCruiser — A style of motorcycle generally equipped with a low seat and pullback handlebars. This style of bike predominantly stems from the customizing of standard American motorcycles in the '60s and '70s.

Displacement — The size of the engine; specifically, the total volume found in the cylinders. This is usually expressed in cc (cubic centimeters) or ci (cubic inches). Generally, the larger the displacement, the more powerful the motor.

DOHC — Dual Over Head Cams. Two camshafts found in the head or top of the engine that open and close the valves. Two cams allow more precise control than one.

Dresser — (also full dresser) Typically, a large motorcycle that is designed for long-distance touring, especially with luggage and a windshield. (See also: Bagger)

Dual-sport — Street legal motorcycles that provide varying levels of off-road capabilities. Not as focused as pure off-road or pure street motorcycles. Also known as dual-purpose

Engine cut-off switch — Usually located on the right handlebar switch housing, this switch allows the motorcyclist to turn off the engine without removing his or her hand from the handlebar. Also known as the "kill switch."

Ergonomics — The study of body posture, and the positioning of instruments, to create a good human-to-machine interface. "Good ergonomics" refers to how well a motorcycle fits a rider for its intended use.

Fairing — Bodywork and/or windshield at the front of the motorcycle designed to deflect the wind. Also used to refer to side panels on, for example, sportbikes.

Flickable and Flickability — Used to describe the agility of a motorcycle, or how quickly a rider can “flick” the bike from side to side in turns.

Forks — The sprung metal tubes that connect the front wheel to the motorcycle triple-tree.

Four-stroke engine — This is the most common engine design found in street motorcycles today. It refers to the number of times a piston moves up and down through each power cycle. 1) A downward stroke brings in the fuel/air mixture; 2) an upward stroke compresses the fuel/air mixture; 3) a downward stroke results when that mixture is ignited and expands, and finally; 4) an upward stroke expels the exhaust gases.

Fuel-injection — (also EFI) A device that serves the same function as a carburetor, but uses computer-controlled jets to inject atomized fuel and air into the air stream going into the engine.

Gypsy Tour — A current AMA touring term that came from the early days of motorcycling, when riders all over the country suited up for a day-long ride to a favorite destination. The implication is that you are traveling without time or distance constraints.

High side — A type of crash resulting when the rear wheel starts to slide in a turn, then suddenly grips, flipping the bike sideways. (See also: low side)

Holeshot — In racing, the drive from a standing start up to racing speed. Generally, the rider who makes the strongest start is said to have gotten the "holeshot."

Horsepower — A unit of measurement used to describe an engine's strength. Typically, the more horsepower an engine produces, the faster the motorcycle can potentially go. (See also: Torque)

Kill switch — See engine cut-off switch.

Line (in relation to a turn) — The predicted or preferred path a motorcycle will make through a turn.

Low side — A crash that results from a wheel losing traction, allowing the bike to fall sideways. (See also: high side)

Motocross bike — A light-weight motorcycle specifically designed for racing on a track. As compared to off-road bikes, the suspension is able to handle harder hits, the power delivery is more explosive, and the gear ratios are different for riding on motocross or other closed-course tracks.

Naked Bikes — Sport or standard motorcycles with minimum bodywork, fairings or windshields.

Petcock — The fuel valve, usually found on the side of the gas tank.

Off-road bike — A motorcycle designed for use in the dirt or off-pavement. They are typically not street legal, but sometimes they have lights and larger gas tanks.

One-off — A product or part that is not designed to be mass produced. It can refer to a one-of-a-kind bolt-on or a fully customized motorcycle.

Pillion or P-Pad — A small cushion designed for carrying a passenger mounted behind a solo saddle.

Rake —The angle the forks are from perpendicular, usually expressed in degrees.

Rat Bike — A motorcycle that's been kept running by any means possible, usually with mismatched parts and minimal maintenance.

Redline — The maximum number of revolutions per minute an engine can run before damage occurs. The name is derived from the actual red line manufacturers typically put on the tachometer.

RPM — Revolutions per minute. A term used to describe how fast a motor is spinning. Also known as "revs."

Roost — The debris kicked up by a spinning rear wheel. Used as a verb, to leave someone behind.

Shaft drive — A final drive system on some motorcycles that utilizes a shaft to transmit power to the rear wheel, as opposed to a chain.

SOHC — Single Over Head Cam. A single cam shaft found in the head or top of the engine that activates the valves.

Spoke — One of the small, straight metal rods that connect the wheel's rim to the hub.

Sport-tourer — A motorcycle that combines some of the handling and power of a sportbike, with some of the amenities of a touring bike, like saddlebags, comfortable ergonomics, etc. Not as focused as either a pure sportbike or a pure tourer.

Sportbike — A focused motorcycle designed for speed and handling. These machines are usually equipped with aerodynamic bodywork.

Sprocket — The parts of the motorcycle that deliver and receive the power to the rear wheel, creating the final drive. The front sprocket runs off the transmission shaft. The rear sprocket is bolted to the hub of the rear wheel. They are connected together by a chain.

StandardStandard — A motorcycle intended for general, all-around street use, typically with an upright seating posture and higher handlebars.

Stretch — Used by customizers, an expression of how much a tank or frame has been elongated from its stock design.

Squid — A term generally associated with a new or reckless motorcyclist seen riding erratically and/or beyond his or her capabilities.

Supermoto — Generally, a style of motorcycle usually built around, and looking like, off-road machines with street tires. They tend to be very light, flickable machines, and are used in a new genre of racing that usually encompasses riding on a mixture of pavement and dirt surfaces.

Tachometer — A gauge that measures how fast an engine is spinning. The measurement is usually expressed in revolutions per minute. Also: "tach."

Tank-slapper — What happens in rare cases when a motorcycle’s handlebars slap back and forth at high speed, often due to alignment, road or trail conditions, or suspension issues.

Thumper — A single-cylinder, four-stroke motorcycle engine.

Torque — A unit of measure describing the twisting force, or leverage, an engine can exert on the rear wheel. Typically, an engine with a lot of torque will have the potential to speed up faster at lower rpms. (See also: horsepower)

Trail — The distance from the front axle’s vertical position on the ground, to the spot in front of it created by drawing a straight line from the angle of the forks.

Triple tree — The two metal plates that connect the fork tubes to the steering stem, sometimes also used as a handlebar mount. Also referred to as a "triple clamp."

Two-stroke engine — A once-common type of engine now found almost exclusively in off-road motorcycles. A two-stroke motor fires once with every two strokes of the piston. 1) Once fired, the downward stroke of the piston delivers power and then draws in a mixture of fuel, air and oil which displaces the exhaust gases in the combustion chamber; 2) the upward stroke compresses the mixture for ignition.

Vintage — Generally refers to the sport of racing non-current motorcycles. While rules and classifications vary, most vintage-class eligible motorcycles were built before the mid-1970s. The country's largest gathering of vintage enthusiasts is AMA Vintage Motorcycle Days.