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360 vs 180 engine

8904 Views 18 Replies 8 Participants Last post by  jbranson
On a twin if the pistons go up and down the same time is that a 180 or 360 engine?

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the honda dream 305 is a 360 degree motor. The superhawk and 305 scrambler are 180 degree engines. I always thought that was really funny because externally the engines look the same.
That is kind of curious, wonder why they did it. I've talked to people who have pressed apart 175 cranks and put them back together as a 180 and then had a new cam ground up. They could never find a definative answer on the dyno as to what made more power. Seemingly not enough difference to matter. I prefer the 360 degree on a small bike because it make the ignition system much simplier and lighter.
From the people I have talked to (old crusty honda techs who worked on these bikes back in the day) it was to give the bike a more british "feel". Honda saw the dream as the touring/commuter bike of the line and wanted the bike to have the same appeal as a triumph or bsa.
Hey...what is an old Yam XS650? They are 360's right?
That was my first brandy new bike...a 77 XS650...loved the way that front wheel moved an inch back and forth at idle.

That makes sense....engine could rotate a full turn or so to build up momentum before a compression stroke.

Did the Brits do a "twingle" 360 degree twin at some point? Both pistons up and down at the same time and firing at the same time?
I know Puch did with their 250s and 350s. Even had a shared combustion chamber. There are some small italian bikes like that too. Not sure of the brits as a factory bike but here is a triumph 750cc twingle flat tracker:
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