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Old 04-17-2018, 08:45 AM   #203 (permalink)
woodsrat
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Quote:
Originally Posted by Xringer View Post
Why two spark plugs? I've heard of a redundant spark plug on an ultra-lite airplane,
but motorbikes don't crash if a spark plug fails..
In the days of big dome pistons and low octane gas it was a way to create a dual flame front so the air-fuel mixture didn't get blocked away from the spark plug by the piston's dome. To be honest with the flat top/dished/low dome pistons used nowadays I'm not sure why they went with a dual plug setup unless it's a way to help eliminate pre-ignition (knocking) in markets with really low octane gasoline.
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