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Thread: Weber DCOE 45s on pinto 2.1 - Idle jet size

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    Bodger

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    Weber DCOE 45s on pinto 2.1 - Idle jet size

    Hi guys,

    Hoping you can advise on the idle jet selection on my twin 45s DCOE on pinto 2,1. Bit of a running issue, spitting and popping from idle to 4K after that it pulls superb! Good for rally ha. Full check been done on car, lifters/valve and ignition timing. Think the issue is possibly with the carb now leaning out on progression from idle to main.

    Looks like I have 55f6 fitted, what would you advise to swop out?

    Click image for larger version Name:	idle jet.jpeg Views:	74 Size:	33.8 KB ID:	86042


    Thanks

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    Re: Weber DCOE 45s on pinto 2.1 - Idle jet size

    Impossible to say. Depends on cam, main jet, air jet, emulsion tube, choke size, ignition timing.

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    Re: Weber DCOE 45s on pinto 2.1 - Idle jet size

    Cam is FL32 - Now running equal and overlap to try and smooth it out but think it made it worse.
    Ignition timing at 29 degrees

    Carb spec

    DCOE 152

    145 main jet
    Air jet 190 I think...
    Emulsion tube F2
    38mm choke

    Will double check these tomorrow but fairly sure they are correct

    Thanks

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    Re: Weber DCOE 45s on pinto 2.1 - Idle jet size

    You mean FR32 or RL32?

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    Re: Weber DCOE 45s on pinto 2.1 - Idle jet size

    Sorry yes FR32

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    Re: Weber DCOE 45s on pinto 2.1 - Idle jet size

    given the cam i would fit 36mm chokes that will bring the main jet circuit into play earlier, you wont loose any power but it will drive better low down

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    Re: Weber DCOE 45s on pinto 2.1 - Idle jet size

    Thanks, okay Graham will look into that.

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    Re: Weber DCOE 45s on pinto 2.1 - Idle jet size

    Quote Originally Posted by Allanscort View Post
    Thanks, okay Graham will look into that.
    it still might be lean through progression, BUT for sure it will come on to the main circuit sooner and be easier to jet and give more low down torque and on an FR32 you wont loose top end

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    Re: Weber DCOE 45s on pinto 2.1 - Idle jet size

    Quote Originally Posted by Graham View Post
    it still might be lean through progression, BUT for sure it will come on to the main circuit sooner and be easier to jet and give more low down torque and on an FR32 you wont loose top end
    Like the sound of that as its a pig to drive low down as is.

    Cheers

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    Re: Weber DCOE 45s on pinto 2.1 - Idle jet size

    You won't believe what a difference dropping a couple mm on the choke size will make to the drivability of the engine. I have a newly built Pinto with a GTS4 cam with 45's and I am using 36mm chokes. The Car isn't quite finished so I haven't driven it up the Road yet but static it revs like a Motorbike.

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    Re: Weber DCOE 45s on pinto 2.1 - Idle jet size

    Yes, smaller choke size make carb tuning a lot easier. Most people use chokes way too big, it does not help. For the kind of power I suspect here, 34mm will be more as needed, probably 32mm (better use 40 DCOE).

    Too many people think they will loose top end power and try to use chokes as large as possible. You would be surprised how small you can take them without any real influence at top power. Very often you gain 5x more of what has been lost at lower RPM's.

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    Re: Weber DCOE 45s on pinto 2.1 - Idle jet size

    Cheers guys, bit weary going down to 34mm...I will drop the chokes to 36mm first and see what its like. Can anyone else comment on that? 36mm looks to be correct for 45s

    Might change the plug leads too to eliminate that side of things.

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    Re: Weber DCOE 45s on pinto 2.1 - Idle jet size

    Quote Originally Posted by Allanscort View Post
    Cheers guys, bit weary going down to 34mm...I will drop the chokes to 36mm first and see what its like. Can anyone else comment on that? 36mm looks to be correct for 45s

    Might change the plug leads too to eliminate that side of things.

    My 2.1 had 36mm chokes in 48 Dellortos and it was very drivable, but then I always thought the 4.6 diff helped too.

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    Re: Weber DCOE 45s on pinto 2.1 - Idle jet size

    Got some 36mm chokes to fit. Be fun trying to swop existing 38mm with the carbs in situ...Have a go anyway, if not carbs off job. They were recently stripped and cleaned, might be lucky!

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