Could low octane fuel cause your 2006 Harley Sportster to cut out?

No, low octane fuel alone should not cause a 2006 Harley Sportster to cut out. Octane is a measurement of a fuel's ability to resist knocking, which is a harsh noise that can occur in engines when the fuel ignites too early. Lower octane fuels are more prone to knocking, but this should not cause a motorcycle to cut out. Engine cutting out is more commonly caused by issues such as a faulty spark plug, a clogged fuel filter, or a problem with the fuel injector.