Saw this today.

BULL

The Blue Puta
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In a mate's bike shop.


 

BULL

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The split-single system sends the intake fuel-air mixture up one bore to the combustion chamber, sweeping the exhaust gases down the other bore and out of the exposed exhaust port.[1]
The rationale of the split-single two-stroke is that, compared to a standard two-stroke single, it can give better exhaust scavenging while minimising the loss of unburnt fresh fuel/air charge through the exhaust port. As a consequence, a split-single engine can deliver better economy, and may run better at small throttle openings.
A disadvantage of the split-single is that, for only a marginal improvement over a standard two-stroke single, the "Twingle" has a heavier and costlier engine. Since a manufacturer could produce a standard twin-cylinder two-stroke at an equivalent cost to a Twingle, it was perhaps inevitable that the latter should become extinct.[2]
There have been "single" (i.e. twin-bore) and "twin" (i.e. four-bore) models.[3] Unusually for a motorcycle engine, some Twingles have the carburettor mounted on the front of the engine, beneath the exhaust.
 

Bruno1969

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Probably a Puch. Two pistons with y shaped con rod

Another famous Austrian bike!
 

Pom17

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Awesome, thanks for sharing
 

FHM_V

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Howzit guys... been a while.... That's wierd, and interesting at what engineers tried in those days....
 

DT_Mania

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I is called a Split-Single (as BULL indicated) that is a twin-piston setup that shares a single combustion chamber. This specific example is a Puch Doppelkolben - 250cc. You will see that both the exhaust ports as well as the carb is front facing, that should makes this a post-war model.
 

Buff

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Twice as much shit to go wrong :icon_e_surprised:
 
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