ET: Engine (Twin) Pilot jet

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Magnetoman

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Those flat slides look the part and would be great in an appropriate installation, but the two turns in that tube play hell with the flow. Although longer inlets can boost h.p. at low rpm, it doesn't take a dyno to know that any help the extra length might give is more than eaten up by the loss of h.p. at higher rpm due to the constricted flow.
 

vibrac

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I seem to remember back when I had a passing interest in racing parallel twins ( Oh! wasted youth) That right angled bends in inlet tracts gave more power than gentle tapers because of better mixing....
 

erik

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What is about the original small bellmouthes on the Amal 276 and 289 carbs?Any influence on power delivery?
 

Magnetoman

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What is about the original small bellmouthes on the Amal 276 and 289 carbs?Any influence on power delivery?
For what it's worth, on the flow bench adding a bellmouth to a 1038 Concentric increased the flow by 0.8%, but on a 1036 it decreased it by 0.3%. However, the differences are small enough that I'd have to say the bellmouth made essentially no difference within experimental error.
 

vibrac

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tant the bellmouth shape or even its length its the whole length of the inlet tract (and a whole host of related factors)
 
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