Float Bowl Jet (?)

[lukasgrech]

Hi all,

I am in the process of re-building my carbs - various reasons.

Upon disassembly, I found that everything was WAAAAY too tight, PO must have been really scared of things coming apart.

One of the results of their overtightening, was that  they probably snapped the brass 'jet' that is screwed into the bottom of the float bowl (Left in the photo).

I have found a decently priced replacement bowl, but could someone please tell me the name of that jet? I don't know what I'm looking for.

I have looked on motorworks.co.uk and cannot pinpoint to which brass jet is the one I require, there doesn't seem to be a 'float bowl jet'.

Any help is much appreciated. Thanks!

[nhmaf]

That is for the enricher circuit of the carb - a.k.a "choke", though it really isn't.

I think that part is supplied from the factory already installed in the float bowl, and that there isn't a practical way to install a replacement - getting a new float bowl is the general remedy if that jet cannot be cleared out (usually they block up with varnish).

someone correct me if I am wrong on this, please-

[Barry]

There is nothing to snap on that jet. I suspect it's just a press fit and agree with nhmaf that a replacement bowl would usually be needed if it can't be cleaned. The actual jet orifice is in the side and that's what probably needs cleaning.

If it was me I would find a way of cleaning it even if it meant drilling it out although I don't where you would find the size except by measuring a good one. I doubt the hole size is hyper critical as it's function is just to slow down the initial excess richness after start up but assuming bowls are common across all airheads I'd be careful about making it bigger as a 650cc engine is not going to need bigger.

[montmil]

Bob has you headed in the right direction.

The brass "jet" in the bottom of the enrichener circuit fuel reservoir can be cleared by probing with a single, thin strand of copper wire; something yanked from a scrap of 16-18 gauge wire.

The jet does nothing more than allow the enrichener reservoir's fuel level to match that of the larger primary bowl reservoir. Note the long, thin brass tube extending from the carb's main body; this tube feeds fuel to the enrichener circuit.

I'm guessing that the brass jet was OEM fitted as the difficulty in casting/drilling a tiny hole at the bottom of an awkward location would have been too time and labor expensive. far cheaper to press in a small jet "fuel passageway".

Confirm the fuel passage is clear, then move on to the rest of your Bing chores. Nothing more to see here, people... move on.

[montmil]

Side bar note:
I'd bet that the screwdriver slot seen on the top of the enrichener jet provided the "gotcha moment" for a PO. Probably was not a bmwr65dotorg member.

"I'll just unscrew this puppy. Humm... a wee bit snug it is. Maybe a bigger hammer will help."  oops.

[lukasgrech]

Thanks everyone!

I've given the carbs a good clean, and the orifice in the bowl is clear (wire and a spurt of carb cleaner confirmed).

I've been thinking that the orifice will not be super critical, so thanks for clearing that up, as long as the passage is clear, saves me buying a new bowl.

Next up, wait for all the new o-rings and gaskets and rebuild!

[Tony Smith]

Ok

Firstly, the float bowl enrichener jet is removable on every CV Bing I have seen, including R100, R80 and as recently as last night, 1985 R65.
 
But, should you try and remove it is another question. You can clean it quite effectively without removing the jet. The purists will tell you to use a copper wire strand stripped from some domestic structural wiring, and if the actual size (or more correctly the amount of fuel flowed by this jet) actually in any way critical I'd almost agree.
 
But, the jet isn't mission critical and in fact BMW use the same size jet (as far as I can see) on all 32mm carbs (and probably the 40mm, but I'm too lazy to look).
 
You can't buy that jet from any of the usual sources, although I seem to recall that Bing Agency in USA has them.

Yours is still perfectly OK, only the brass screwtop has been snapped off in the course of someone's enthusiasm - just ignore the hell out of it.
 
If you cannot find a piece of copper wire to donate a strand, either pull a strand from a wire brush, or visit your local welding place and buy a set of jet files.
 
Now listen carefully. A jet file used indiscriminately will destroy a "critical" jet in seconds by removing metal from within the jet, but you will buy a set that do not have the "file" the full length of the jet file, the end makes a perfect probe to GENTLY push through a blocked main or idle jet, or through the orifices in the emulsion tube. I have been using jet files for decades and the only jet I have ever buggered up was the first one I worked on. The secret is to always use a file smaller than the jet orifice you are clearing.