Why 5 valves?


Piston Go Up

Spark make Spark Uggggg

Gas go Boom

Piston go down

Piston Go up

Exhaust Valves open Ugggg

Bad Gass Out Wheeeewwwwwwiiiieeeee Uggg

Piston go down

Intake Valve open Ugggg

Good Gas come in

Go back to top Ugggggg


So that is caveman terms of what happens in the engine, So why 5, Becouse 4 is not enough and 6 is too many.....Uggggg

Motogreg hit on it. If you look at the available area in the head versus the area used up by round valves you use up a little more of the available space with the five valve configuration which potentially allows more air to flow. I think the reason they don't bother under a certain size cc is that the extra complexity and wieght is not worth the gain in airflow.

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