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The Four Stroke EngineName:_

The Four Stroke EngineThe sound o a Harley-Davidson motorcycle is highly recognizable and unmistakable. But whatcauses that signicant sound?

The heart o a Harley-Davidson motorcycle is the engine. Harley-Davidson motorcycles arepowered by an internal combustion engine. This means the engine burns uel inside.

There are our strokes or stages in the engine cycle. The our strokes o the cycle are intake,compression, ignition, and exhaust. Bike lingo or this is: suck, squeeze, bang and blow. Each 180

degree turn o fy-wheel is one event stroke. The fywheel must make two revolutions to completeone power cycle o the motor.

In the picture above, label the ollowing parts o the engine: cylinder, intake valve, exhaust

valve, piston, fywheel and spark plug. The rst letter has been lled in or you.

Use one o the ollowing websites to see a our stroke engine in motion.

http://www.k-wz.de/vmotor/v_omotore.html

http://en.wikipedia.org/wiki/Internal_combustion_engine

http://auto.howstuworks.com/engine1.htm

WORD BOXcylinder A chamber in which a piston slides to compress a fuid

exhaust valve A valve though which burned gases rom a cylinder escape

fywheel A heavy wheel that stores kinetic energy and regulates the operation o

an engine

intake valve A valve that controls the fow o uel-air mixture to be drawn into the cylinder

piston A round piece that ts inside a cylinder and moves up and down underfuid pressure

spark plug A device that ts in the head o an engine cylinder that ignites the uel-airmixture by means o an electric spark

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The Four Stroke Engine (contd)

Are you interested in learning more about how technology is used in the design o motorcycles?Visit www.buell.comto learn more about the Trilogy o Tech.

Intake Stroke

During the intake stroke, the fywheel draws

the piston downward drawing in an atomizedmixture o air and uel into the cylinder.

Compression Stroke

The intake valve closes. The piston movesupward and compresses the air/uel mixture.

Ignition Stroke

When the piston reaches the top, the sparkplug res and the compressed air/uel mixture

explodes. As the mixture burns, it expandsdriving the piston downward again.

Exhaust Stroke

The piston moves up the cylinder and the

exhaust valve opens allowing the exhaust toescape and the process starts again.

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