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General Terms

• Sportbike – A type of motorcycle first engineered during the 1980’s to provide the characteristics of speed, acceleration and agility for the sport-minded, adrenalin driven rider.  Combining a high performance engine, aerodynamic body, and race bred components into a motorcycle designed to give the everyday sport rider the power and handling usually associated with a race bike.   Split into three different categories; Super Sport, Super Bike, and Hyper Sport, defined by the displacement of their high performance engines.
  
• Custom Sportbike Terms- Superbike, sport-tourer, street bike, stunt bike, roadracer, streetfighter, turbine bike, dreambike, sport classic, freestyle bike.
• Slang Sportbike Terms- Crotch rocket, bling, sex-on-wheels.

• Engine -- Simple motorcycle engine is composed of a cylinder, piston, connecting rod, crankshaft, and crankcase.  The piston slides up and down in a cylinder, connected to a rod, which transfers work-done (movement) by the piston into the rotational movement of the rod and then the crankshaft.

To work an engine needs air, fuel, compression (pressure built up inside the engine chamber) and combustion (burning of the air-fuel mixture) to produce the power to allow the motorcycle to move.

The simple motorcycle engine performs the following simple functions:

• Produce a vacuum which pulls air and fuel into the cylinder.
• Compress the air-fuel mixture to produce efficient combustion.
• Ignite the air-fuel mixture under pressure.
• Use the resulting combustion pressure to do work.
• Remove the waste products produced by combustion reaction.

When these requirements are provided in proper proportions and sequence, the simple motorcycle engine runs.
For the simple motorcycle engine to form a vacuum and compress the air-fuel mixture the cylinder must be sealed.  This task is accomplished by the cylinder head, pistons, and piston rings working together to seal the chamber.  They produce a relatively leak proof enclosure that is called the combustion chamber.  Then, when the piston moves down, a vacuum or low pressure area is developed in the cylinder and as the piston moves up the mixture is squeezed under pressure.

To allow the air-fuel mixture into the cylinder, an intake valve and port (passage) are required.  A smaller exhaust valve and port valve allow the burned gases to exit the engine cylinder.

Engines come in two stroke, four stroke, three stroke configurations and other multiples of stroke.

• Custom engine terms- V-twin, liquid cooled parallel twin, 4-stroke liquid-cooled, 90 degree 4-stroke L twin, liquid cooled transverse 4-stroke four, inline-four with 4 valves per cylinder, two-stroke parallel twin, 60 degree v-twin, air-cooled Desmo v-twin, Desmodue Dual Spark engine, inline three.
• Slang engine terms- Powerplant, mill.  

• Cafe' Racer - A type of motorcycle stripped down of all unnecessary weight to allow for maximum speed, and originally used to race from transport cafe to transport cafe in the 1930’s and 40’s by individuals referred to as Rockers.  The engines were tuned for maximum velocity and were originally used for what the Rockers referred to as Juke box racing.
  
  
• Cylinder - The sealed metal enclosure around the piston that provides space for the piston to move up and down, squeezing the air-fuel mixture under pressure and making combustion possible once ignited by an electrical sparkplug. 
  
  
• Piston – A solid metal piece attached to the connecting rod that moves inside a cylinder of a motorcycle engine to increase pressure on air-fuel mixture within and facilitate combustion in combustion chamber.
  
  
• Connecting rod – Metal piece attached to piston and crankshaft that is used to transfer reciprocating motion of piston to the rotational motion of crankshaft used to power the motorcycle.
  
  
•  Crankshaft – A metal piece attached to connecting rod that is used to transfer reciprocating movement of piston into rotational motion used to produce power to move a motorcycle.
  
  
• Crankcase – Airtight enclosure used to enclose the crankshaft of a sportbike engine.
  
  
• Four-stroke engines - A four-stroke cycle engine requires four up-and-down piston movements or strokes to complete one full cycle.  
  
  
  • The first downward piston movement, while the intake valve is open, is the intake stroke.  When this occurs, the air-fuel mixture is pulled into the cylinder.
  • The compression stroke is the first upward piston movement, which pressurizes the air-fuel mixture.
  • The second downward stroke piston movement is the power stroke, caused by the heat, expansion and pressures of combustion.
  • The exhaust stroke is the second upward piston movement, which occurs while the exhaust valve is open, pushing the burned air-fuel mixture from the engine.

Each stroke rotates the crankshaft one-half revolution (180 degrees).  To complete one full cycle, the crankshaft must make two complete revolutions, resulting in the operation of a four-stroke engine.

• Custom four-stroke terms – Liquid cooled parallel twin four-stroke, liquid cooled 90 degree 4-stroke L twin, liquid cooled transverse 4-stroke four, inline four with 4 valves per cylinder.
• Slang four-stroke terms – Four-bagger.

• Two-stroke cycle engines – A two stroke cycle engine produces power once during each crankshaft revolution.  It has a power stroke twice as often as a four-stroke cycle engine.  Most of the fundamental parts are the same (crankshaft, crankcase, connecting rod, pistons, rings, cylinder and cylinder head).  The primary difference is in the method of controlling air-fuel mixture flow into and out of the engine.

In a two-stroke cycle engine, the same events take place as in a four-stroke engine.  However, the two-stroke cycle events are controlled and overlap differently.
The differences between two-stroke and four-stroke cycle engines are:

• Two-stroke cycle engines have a power stroke every revolution of the crankshaft.
• Two –stroke engines do not use valves.
• Two-stroke cycle engines pass their air-fuel mixture into the crankcase before reaching the combustion chamber.
• Intake and exhaust timing is controlled by the piston, not the valve mechanism.

Since two-stroke engines produce power once every revolution, several events must happen at the same time.  A few two-stroke characteristics should be explained before two-stroke cycle operation can be fully understood.

• Flow through the engine is controlled by the piston covering and uncovering three cylinder ports (openings) in the cylinder wall, called the intake port, transfer port and exhaust port. 
• Air-fuel mixture enters the crankcase below the piston and then is transferred from the crankcase to the area above the piston.
• Burned air-fuel mixture is exhausted during the power stroke.
• Slang two-stroke terms – Two-bagger.

• Speed – The measure of the distance traveled by a sportbike divided by the time interval required to complete the entire journey in feet/second (meters/second).
• Slang speed terms – Pure adrenalin.
  
  
• Velocity – The measure of the distance traveled by a sportbike, in a particular direction, divided by the time internal needed to finish the entire trip.  Velocity differs from speed in that a velocity always has a direction component and speed deals only with the total distance traveled divided by the time required to travel the distance.
  
  
• Acceleration (deceleration) – The measure of the changes in magnitude and direction of velocity of a sportbike as it moves, a sportbike is then said to have acceleration.  Acceleration is measured as the rate of change of velocity with time in units of ft/s/s.
  
  
• Agility – 1. The ability of a sportbike to move around easily, to get in and out of tight spots.  2. A measure of how easy the sportbike is to move around while it is in motion from the rider’s perspective.
  
  
• Motorcycle – A motorized two-wheeled transport (even three wheel today) design to be driven by a human being from point A to point B.
  
  
• Aerodynamics – Aerodynamics is the science of the flow of air and/or of the motion of bodies (in this case sportbikes) through the air.  It is associated in this case with achieving flow or movement through the air with maximum efficiency and is accomplished in sportbikes with the exterior shape of the sportbike being designed to let the air flow freely over the surfaces of the sportbike that contact the surfaces during movement.
  
  
• Litre Bike – A high-powered sportbike with an engine displacement close to 1000cc.
  
  
• Super Sport – A sportbike with high revving engine and a displacement between 600 – 800 cc, producing over 100 horsepower and weighting between 350 – 450 lbs. 
• Slang Super Sport terms – Middleweights.
  
  
• Super Bike – A sportbike with a high revving engine and a displacement between 800 – 1100 cc, producing over 140 horsepower and weighting between 440 – 480 lbs. 
•    Custom Super bike terms – Litre bike.
  
• Hyper Sport – A sportbike with a very high revving engine and a displacement between 1100 – 1400 cc, with over 150 horsepower and producing speeds over 180 mph, and they generally weight close to five hundred pounds. 
• Slang Hyper Sport terms – Big bore.
  
  
• Cylinder ports – Ports used in motorcycle engines to allow movement of gases during various phases of the engine operation.
  
  
• Throttle – A device that controls engine speed of a sportbike by restricting the flow of air and fuel into the engine.
  
  
• Exhaust valve -- The exit through which the exhaust gases exit the cylinders of a sportbike during the exhaust stroke of a four cylinder engine operation.
  
  
• Cylinder head – A metal casting that caps the cylinder of a sportbike.  It contains the combustion chamber, the spark plus and, in a four stroke engine, the valves.
• Slang cylinder head terms – Heads.
  
  
• Combustion – 1. Burning. 2. Development of light and heat from the chemical combination of a substance (in this case fuel) with oxygen.
  
  
• Combustion chamber – The area in the cylinder where the act of combustion takes place in a sportbike engine.
  
  
• Spark plug – Device that screws into the engine’s cylinder head and produces electric spark that jumps across the electrodes and ignites the compressed air-fuel mixture in the cylinder during the power stoke of sportbike engine operation.
  
  
• Vacuum – A space (in this case a cylinder) devoid of matter, typically measured by the total pressure of the residual matter in the cylinder which is pumped.
  
  
• Compression – 1. The act of compressing. 2. Reduction in volume of the fuel mixture in a sportbike engine, during the compression stroke of a four cycle engine, before ignition.
  
  
• Intake valve – The valve in four cylinder engines, that the vacuum created in the cylinder draws the fuel-air mixture past, during the Intake stroke of engine operation.
  
  
• Intake port – Passage in engine cylinder that lets the air-fuel mixture flow into the crankcase of a sportbike.
  
  
• Compress – 1. Squeeze together. 2. Bring into a smaller space or shorter time.
  
  
• Piston rings – Metal pieces used in conjunction with the piston and cylinder head to seal the cylinder to allow compression to occur in the engine of a sportbike.
  
  
• Transfer port -- Passage that connects the crankcase to the upper cylinder in two stroke engines.
  
  
• Exhaust port – Passage through which the burned exhaust gases leave the engine cylinder during the operation of a sportbike engine.
  
  
• Intake stroke – The first part of the four part cycle of the operation of a four cylinder engine, when the piston moves from its highest position to its lowest position in the cylinder.  Creating a vacuum that draws the air-fuel mixture past the open intake value of the sportbike.
  
  
• Compression stroke – The second part of the four part cycle during the operation of a four cylinder engine, the gases are compressed during this phase to allow for proper combustion to occur in the combustion chamber of the sportbike.
  
  
• Power stroke – The third part of the four part cycle during the operation of a four cylinder engine,  in which the air-fuel mixture ignited by the sparkplug expands rapidly, causing tremendous heat and pressure used to push the piston down in the cylinder and transmit power to the crankshaft of a sportbike.
  
  
• Exhaust stroke – The last stroke in the operation of a four stroke engine in which the piston moves up the cylinder, pushing the burned gases past the open exhaust valve, leaving the cylinder empty and preparing it for the next four stroke cycle of the sportbike engine.
  
  
• Detonation – An undesired form of combustion that results from heat driven changes in the fuel-air mixture as normal combustion proceeds.  It typically attacks the outer edges of pistons and cylinder heads because it occurs near the very end of combustion.
  
  
• Track – The surface upon which a sportbike is running, be it dirt or pavement.
  
  
• Headlight – The electric light located on the front of a sportbike to provide light for riding the sportbike in times of poor visibility.
  
  
• Instrument cluster – The dashboard in the front of a sportbike containing all the gauges, meters, switches and indicators to tell the rider important information on the sportbike while it is being driven.  Generally it contains speedometer, tachometer, oil gauge and related meters, but custom additions of any device to the instrument cluster are occurring in the sportbike industry constantly.
  
  
• Foot pegs – Footrests generally located toward the rear in sportbikes to provide a firm base for the rider’s feet to rest upon.
  
  
• Lean angle – The maximum angle from horizontal a sportbike can be leaned over while traversing a corner turn.
  
  
• Stock – A term referring to a sportbike having come directly from the factory with parts normally seen on all units leaving the manufacturing line.
  
  
• Scrub-off-speed – A term referring to a sportbike rider downshifting to reduce the number of engine revolutions and thereby slowing the sportbike down.
  
  
• Tire conditions – The environmental conditions of the surface that the sportbike tire will be running on snow, rain, hot, or maybe oil on the surface.
  
  
• Weight bias – The uneven weight distribution of a sportbike, toward either the front or rear of the sportbike.
  
  
• Jixer -- A sportbike constructed with mix-matched custom parts.
  
  
• Wheelie bar – Training bar added to the back of sportbike when a rider is first learning to wheelie, it prevents the sportbike from flipping completely over during the wheelie.
  
  
• One-handed circle wheelie – A sportbike stunt where the rider spins the sportbike in circles using only the throttle hand to hold onto the sportbike with while revving it.
  
  
• Crazy Larry – Sportbike stunt where the rider smokes the rear tire while spinning the sportbike in 360 degree turns.
  
  
• Contact patch – The area of the tire in contact with the surface it is running on.
  
  
• Exhaust note – The sound made by the exhaust of a sportbike when running.  Originally attributed to Pope Benedict XVI when he commented on the sound of the 999 Ducati Superbikes being a cardinal sin.
  
  
• Oomph – 1. Get up and go. 2. Acceleration of the sportbike. 3. The power of a sportbike.
  
  
• Handling – The agility of a sportbike, the ease with which a sportbike is manoeuvred or controlled during operation.
  
  
• Street rankings – How the riders rate a sportbike for riding on the street as compare to other sportbikes.
  
  
• Spunky – Quick and fast sportbike with attitude.
  
  
•  Taillights – Red light on back of sportbike to signal that the bike’s brakes are in use and the sportbike is slowing down.
• Slang taillight term – Undertails.

 

•  Fenders – Rounded metal pieces designed to cover the top of the tires and protect the sportbike rider from debris thrown up by the wheels.
• Slang fender terms – Huggers.
  
  
• Stretch – Lengthen the sportbike with a longer swingarm.
  
  
• Handle bar – Steering bar of the sportbike where the riders hands grip the bike and upon which are located the gear lever, brake lever and clutch lever all used by the rider in the normal operation of a sportbike.
  
  
• Chassis – Base frame of the sportbike upon which all the components of a modern sportbike will be placed.
  
  
• Fairing – Streamline body panels covering the exterior portions of the sportbike used to enclose interior parts from damage, increase aerodynamics and/or rider comfort.
  
  
• Cam lobes – Use in four stroke engines to control the valve openings during combustion.
  
  
• Compression ratio – The ratio of the volume above the piston at BDC (full expansion), to the volume above the piston at TDC (full compression), is arbitrarily called the compression ratio.
  
  
• Electronic Fuel-injection – Device mounted in each intake port that controls that amount of fuel entering each cylinder of a sportbikes engine.
  
  
• Oil tank – Metal container used for holding the oil separate from the fuel in some four stroke sportbikes.
  
  
• Manu – French sportbike stunt rider generally considered to be the best French stunt rider in the world.
  
  
• Sportbike ergonomics – The study of the relationship between a sportbike and its riders toward the goal of providing a more rider friendly sportbike.
  
  
• Light steering – Referring to a sportbikes ability to be steered easily while in operation.
  
  
• Grip – The amount of traction a tire is getting against the surface on which it is running.
  
  
• Stopping power – The measure of the ability of a sportbikes braking system to stop a sportbike.
  
  
• Numb brakes – Brakes that have no feel to them, that don’t seem to allow for fine adjustments while riding.
  
  
• Throttle response – The time delay between when you turn the throttle of a sportbike and the engine responds with power, typically there is always some delay.
  
  
• Throttle abruptness – Similar to throttle response, throttle abruptness is the amount a throttle must be applied to get the desired response.
  
  
• Powerband – The area in a sportbikes gear range where the power received from the engine is the smoothest and the sportbike is at maximum performance.
  
  
• Front end feedback – The overall feel of a front end of a sportbike while the rider is running down the road.
  
  
• Throttle application – The amount a throttle needs to be turned for a sportbike rider to successfully complete an action.
  
  
• Saddle time – 1. The amount of time a rider has spent riding a sportbike in their life. 2. The amount of time a rider has spent on a sportbike during a particular action.
  
  
• Top speed – The maximum distance that can be traveled in a specific amount of time by a sportbike.
  
  
• Fuel range – The maximum amount of miles (kilometres) that can be traveled, on average, by a sportbike with a full tank of fuel.
  
  
•  Exhaust Pipes – Metal tube that allow exhaust gases to vent from rear of bike, that in modern sportbikes acts as a form of pump to help empty and refill your engine’s cylinders.
  
  
• Leg room – The maximum amount of space a sportbike has for the rider to stretch out their legs while riding a sportbike.
  
  
• Displacement – The amount of volume a sportbikes engine has for combustion to occur within the engine.
  
  
• Transmission – A collective term for the sportbike components responsible for transmitting power from the engine to the rear wheel of a sportbike.
  
  
• Saddlebags – Containers designed to be attached to a sportbike to carry a rider’s cargo, equipment or whatever the rider wishes to transport.
  
  
• Open throttle – The point at which the sportbike throttle is fully open and cannot be opened further.
  
  
• Peak horsepower – The maximum amount of horsepower that a sportbike can achieve.
  
  
• Rubber/road interface – The point of contact between the tire and the surface the sportbike is running on.
  
  
• Ton – 100 miles per hour on a sportbike.
  
  
• Middleweight – Sportbike in the Super Sport category with an engine displacement in the range of 600 – 800 cc.
  
  
• Ignition –The moment when the fuel/air mixture is ignited in the combustion chamber of a sportbike, or the system that ignites it.
  
  
  
• Swingarm – A suspension member pivoted at one end of a sportbike and supporting the wheel at the other.  In most cases, the swingarm is more accurately described as a pivoted fork, since the wheel is supported at both sides.
  
  
  
• BDC – Bottom dead center; the point during the crankshaft rotation at which the piston is in its lowest possible position.
  
  
  
• TDC – Top dead center; the point at which the crankshaft and piston are in their highest possible positions.