A piston fires

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A piston fires. The next piston fires at 315°. There is a 405° gap. A piston fires. The next piston fires at 315°. There is a 405° gap. And the cycle continues.

What is being described?

Answer: (select the text below to show)

The production of the Harley-Davidson “potato-potato-potato” sound.

Question by Sumant Srivathsan