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In a 4 stroke engine there are 2 ups and 2 downs. compression/exhaust, intake/power. So a full 4 stroke cycle is indeed 720* of revolution. but the spark likely fires every 360 or even 180...but I don't think this relates to the noise. Its hard to diagnose as you sort of have to move around feel out a noise location.
I am not inclined to suggest your engine needs re timing or a tear down.
To me the sound I hear is in tandem with the exhaust pap. So I would start at the muffler tip check and tighten every fixing all the way to the header flange. Something sounds loose and or is making contact with something else but not necessarily from inside the engine.
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