I'm Brian Bussemey from Cowboy Harley Davidson of Austin. We will be explaining how a motorcycle engine works. This is a four stroke engine. An engine is essentially a big air pump. It has to suck air in. Air goes through the intake. Your air filter is situated out here. Air comes in the intake. Your air filter is situated out here. This is your intake manifold. Air flows in through here and ends up in the intake port of the cylinder heads, flows through there, comes in our intake valve. This is the combustion chamber. Our air enters the engine. Our piston is situated inside the cylinder. The piston moves down with the fly wheel sucking air into the cylinder and then our piston starts moving up. As it moves up in the cylinder it is compressing the air mixture that's in the cylinder into the cylinder head. Our spark plug fires off the mixture, it ignites. When it ignites it pushes the piston back down the cylinder again and back up. On its way back up the exhaust gases that are in the cylinder go through the exhaust valve and out the exhaust port and into our exhaust system. To control the air flow moving in and out we have our cam shafts which are connected to the crank shaft on the engine and turn with the crank shaft. Our cam shaft has lobes on it that are lifters ride around, the lifter pushes up on a push rod which is in a chrome tube on the outside of the engine and operates our rocker arms. Our push rod fits into the rocker arm. When our cam shaft rotates around it lifts the push rod which lifts this rocker arm which pushes these valves down. That's what initiates the air flow in and out of our combustion chamber. We also have an oil pump which is connected to the end of the crank shaft as well so when your crank shaft is turning your oil pump is turning also giving us oil pressure. All of this occurs to turn this crank shaft which is connected to the transmission and to the rear wheel and gives us power to our motorcycle. I'm Brian Bussemey from Cowboy Harley Davidson of Austin. This is how a motorcycle engine works.