Boxer engines got their name because each piston moves simultaneously in and out rather than alternately, like boxers showing they're ready by clashing their gloved fists against each other before a fight.
RustyKnight In: Newton Aycliffe
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According to BMW the very first shaft drive bike with flat engine layout was called a Spagthorpe Boxer so every flat engine after that was called a 'boxer'.
Incorrect RK.
Just because an engine is a flat design it does not make it a Boxer type.
ONLY an engine that has pistons that move simultaneously in and out together, rather than alternately, are called boxer's
On a boxer engine, each con rod has its own crank pin as opposed to two rods sharing a crank pin.
On a flat engine the pistons would move in relation to each other i.e. one at TDC & one at BDC.
ONLY a boxer engine has two pistons ( use the BMW 2 cyl engine as example ) that will have both pistons at TDC at the same time.Conversley, both pistons are at BDC at the same time.
That is the definition of a boxer engine.
The correct name is horizontally opposed, then the number of cylinders. For example Alfa Roneo flat 12. This engine is a twelve cylinder horizontally opposed lay out. The boxer term came about because the piston and conrod moves like a boxers arm and fist. Not all BMW aircooled engines are called boxers because they made single cylinder engines aswell, which were half of the boxer engine.
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