Solex emulsion tube tuning

[Fordy]

I'm just leaving this here so I have a log of what i'm doing and so others can see the results. trying to eliminate the low end rpm richness from having to close the ac jet to stop high rpm/lean

standard solex emulsion tube
code 4e
34mm long
4.5mm thick
holes are from bottom
4mm up, .8mm hole, 2 holes
8mm up, .8mm hole, 2 holes
15.5mm up 1.2mm hole, 2 holes
19.8mm up 1.5mm hole, 4 holes
23.7mm up .8mm hole, 4 holes

[GTphil]

That's what you call fine tuning

Interesting how the size of the holes goes up then down again along the tube.

What are you going to change first?

[Fordy]

There's 4 small holes at the very bottom.

I'll carefully solder the bottom 2 up and this should bring my top end fueling richer.

Then should be able to take my Ac jet back up from .85 to a 0.9-1mm to bring the low and mid range fueling back leaner.

[James5]

I have seen this done before on the ole VW bettle turbo conversions they solder the lower 2 holes up and as you say will richen up fueling higher up the rev range. From memory doing this gives the VW lump a flat spot, be interesting to see if the C1J does the same

[GTphil]

The solder will have to be uber carefully done, my c1j ran like a bag of spanners with some sh1t in the emulsion tube. I'm imagining with even the smallest bit of obstruction it will cause poor running. With careful solder i can't see why it won't do the job.

[michael tierney]

"trying to eliminate the richness from having to close the ac jet to stop high rpm lean"
is that high boost lean....or just going lean when ur at about 4000 rpm?

[Fordy]

Theory is sound.

Phil got an idea of how to solder it, going to find a drill bit that goes down the tube from the ac jet and then solder the holes up. Should stop the solder going anywhere I don't want it too

Weather is pants atm so until some clear weather I won't be able to test,
I'll run a current log of before and after afr from the aem into the laptop so I can clearly show the differences

[Matt Cole]

Interesting!

[Fordy]

Weathers still shit so not tested yet.

But I have got the tube soldered up for the first test

Found the shank of a 2.5mm drill bit fits perfectly inside the tube
Blowtorched and soldered with the dril bit in place to stop the solder going anywhere but the hole

The Vw story I also found on the net, that problem i'm guessing is from having a solex carb on a engine that its not mean't for and the fact it came from a scrapyard. So probably had a load of dirt inside most of the jet and pump jet for the common stutter flat spot

[Woznaldo]

I'll be following this with great interest. I have tried a few different things to get rid of low end richness, but never really solved it as it improved once I rebuilt the carb.

Thanks for keeping us in the loop with your experiment.

[Fordy]

i'm going to pull the other spare tube I have here and solder up all 4 bottom small holes

So I can quickly swap them around, I have a stock tube, 2 hole removed and 4 hole removed