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Old 06-02-2012, 02:08 PM   #836
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Joined: Jun 2004
Location: Nor Ca.
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Originally Posted by HappyHighwayman View Post
I apologize for the ignorant way I phrased the question, what I was looking for (and you answered) was the "type" i.e. 360 degree. What does it mean that "only one is on the power stroke"?

It takes two rotations of the crankshaft (720 degrees) to go through all 4 cycles of a 4 stroke motor(Intake,compression,power,exhaust). When 1 piston is in the Compression stroke(TDC) , the other is finishing the exhaust stroke. The only other option for a vertical twin and still be called a 360 would be if both were on the compression stroke. A Twingle. The same as a single cylinder engine only in duplicate.

It is the position the pistons are in relation to the bore that makes the determination of a 360 engine. The opposed piston BMW is a 360, because both pistons are at TDC at the same time, they too are on different strokes.
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itsatdm screwed with this post 06-02-2012 at 02:55 PM
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