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Dellorto DHLA 45 Has No Fuel Main Jets  Rating:  Rating
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 Posted: 11-25-2013 12:08 am
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patkennedy
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Bought a 74 JH with twin Dellorto 45's.  Decided to rebuild them and found that the emulsion tubes were not fitted with fuel main jets. Has anyone heard of this arrangement? Seems strange.

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 Posted: 11-25-2013 12:24 am
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Jensen Healey
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Wow! Another new poster on the board. Welcome!

I'm not sure how the main jet could be installed if not pressed onto an emulsion tube. The main jets are about 1cm long.

Kurt

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 Posted: 11-25-2013 12:31 am
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patkennedy
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Sorry, I should have been more clear.  When I removed the emulsion tubes in both carburetors none had main jets pressed in at the bottoms.  Is this a way to get maximum fuel into the tubes or did someone build or rebuild the carbs and forget to fit the jets?

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 Posted: 11-25-2013 05:43 am
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subwoofer
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If the engine ran at part throttle or above the jets must be there. But unless you look closely enough the parting line is hard to see, so they look like a part of the emulsion tube.

--
Joachim

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 Posted: 11-25-2013 12:14 pm
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patkennedy
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Here is a photo of all four main emulsion tubes that I removed from my 74 JH equipped with Dellorto 45 carbs.  They don't seem to have fuel jets. Is this something strange or were they purposely left out in order to make the engine perform differently than if they were installed?  Any help would be appreciated.

Thanks,

Pat

Attachment: JH emulsion tubes without fuel jets4.jpg (Downloaded 49 times)

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 Posted: 11-25-2013 02:12 pm
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Jensen Healey
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Weird. Did the engine run above 3000 rpm? That's when the main circuit cuts in. I've never heard of this "performance" technique.

Maybe the jets stuck at the bottom of the bores.

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 Posted: 11-25-2013 03:56 pm
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patkennedy
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I've driven the JH over 100 miles and had it reved up to about 5000rpm with no problems. Also checked the bore holes and no sign of the jets at the bottoms.It ran rough at idle and there was a dead spot when accelerated. Will have to find a US distributor for some main jets #140. Any additional thoughts?

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