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More carbs-not for the faint of heart

1472 Views 19 Replies 4 Participants Last post by  terrymc
Hey all,
I have disassembled the carbs and split them from the rails (unhhhh) for a cleaning and rebuild.

After I took the slides out, I turned them upside down. I heard something metal fall out of the carbs-only number 1 and number 3. It turns out to be two little brass cylinders about 4mm in outside diameter tapering to about 2mm, with a very small through hole in the middle (maybe 0.5 mm in diameter). There are fuel stains (grey dust) on the tapered end. I looked in number 2- no such device.

Anyone have any idea as to where these things go?

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Hmmmph! Any photos possibly? :razz:
It seems we have been hacked by some scum bags - we're all trapped in a virtual world... aaaaaaaargh! :-D :???: :mad: :evil: :(
Did these parts come from the carb body or the sliders?
How long are the parts, do they have just the one hole in the end or more holes in different places. Yes pictures would be a big help.
My first guess however is the emulsion tubes, they may have been poorly seated during some previous work and fallen out the No2 carb probably has one but it's firmly pressed home and will not fall out. However this is a pure guess so lets have a few more clues and we'll see if we can't solve your mystery.

Ok, I can't seem to operate the digital camera that my neighbor gave me, so, pics may be a long time in comming.

The length of the brass is about 6mm. The hole goes all the way through lenthwise. They fell out of the carb bodies.

That's about it. I know that net diagnosis is difficult at best.

Otherwise-we got hacked? Is that why I don't have any personal messages stored?

We got hacked, yes! :mad: I managed to post only via 'history' and got to my last post, here, then, as it were - see hang out for details !
6mm sized jets, na! Possibly they're the mains - I'm sure you'd know them. This link has a bunch of photos, scrolling down there a close up of the float chamber & some guys fingers holding the emulsion tube where the tube screws in just past there's a little tube of brass, set in the casting - ? The carbs are CV's and similar but not the same - check it out though you might find some thing helpfull. :razz:
I believe I've learned something. Between you all here and a mechanic friend of mine I believe I am referring to the needle jets. The two that I have fit tapered end into the bits that screw into the emulsion tubes. The other end perfectly receives the needle. See, all this time I thought the jets were just the threaded bits that screw into the emulsion tubes.

I think the case is solv-ed (per Clouseau). Now all I have to do is find the one that is missing.

One question: Are these interchangeable or specific to the threaded size (i.e. 125, 127.5 etc)?

It's a learning experience. Thanks for the advice all.

125,127.5 are these numbers on the parts!? Those are the main jets, which screw into the emulsion tubes and the needles are doing the old in/out, 'cos they are attached to the slide which move up and down as you vary the throttle. I would imagine you have 127.5,125,127.5 - the 125 is for the middle carb. If you look at that link I sent you - yes it is a Harley site - take a butchers at the exploded carb diagram. You will notice that
# 5 says needle jet, it is infact the top of the emulsion tube. The needle is that bit that you can see right in the middle between the slide and emulsion tube. Further on that site you'll see a Dynojet kit - the needle jet is that long bit! :-D

I can't get to that site...

The parts with the numbers are the main jets. They screw into the bottom of the emulsion tubes.

The needles attach to the bottom of the slides and move up and down the tube as dictated by engine vacuum.

The bits I began the thread about have a very small hole in the tapered end and a very large hole in the non-tapered end. The non-tapered end holes are the exact size to act as 'female' ends to the needles' 'male' ends. These bits fit neatly into the end of the emulsion tubes and allow the mains to screw into the threaded end of the emulsion tubes.

It is the only place I can figure that they go.

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mmmm! With out photos it hard over the internet, do they have marking, #'s anything? :razz:
Try this site they have images of every single jet type imaginable. Go to Products, then scroll down to Mikuni jets and see if you see anything familiar. :razz:
I have pictures in electronic format. How do I post them here?
Here are the pictures of the part in question:

The part in question is the very small bit on the end of the needle and otherwise by itself (keys for scale).

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Yikes! - the needle is obvious, so is the emulsion tube and that other jet on the right looks like a main fuel jet - the other 'bit' is a mystery. if you go back to this link go all the way down to the bottom, third foto from last with the guy's hand holding the emulsion tube - there is a piece of brass with a hole in it stuck in the carb just above where the e/tube goes - do you see? Maybe that's what that mystery piece is - apart from that, well...... :???:
yeah, thanks for looking and your input. I have asked around and the local euro parts guy said that he thought it was logical to assume the outside carbs use this as a sort of accelerator pump.

What'dya' tink?

Na! there's no accelerator pump on these carbs !
I did not see the part in the microfish but check out this site maybe you'll see it


If not have you talked to anyone at Hinds the owner use to race one and is a good friend of mine. one of the mechanics Dave G. also own a 96 like mine. so maybe between them they have seen this before. No promises on my part but maybe they can help.

Edit: Formatted URL. -Kit

[ This message was edited by: KitNYC on 2007-05-16 16:49 ]
Hi Terry,
Thanks for the advice. I know Jeff races in the Bonne series. I've had mixed experience with them and others I know have had quite bad experience. Not a bad idea to ask them though (especially with a specific person to ask for).

Yeah Jeff races in the thruxton cup and vintage superbikes now. but his first race bike was a 95 speed triple that I think he raced in BEARS I could be mistaken about the last part. one thing that I have found over the years in business is that no matter how good or bad you are that there will always be a time that someone will have a bad experience. So I can understand if you had a bad experience.
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