Weber, Carb Balance Options

[NARP74]

I was starting to balance my carbs, never looked into them since I bought the car. I ran into some issues with my carbs vs the standard docs I find.
One bank reads 4.5 and 5, the other bank reads 6 and 6 with the snail. When I looked into adjusting the lower reading one, I noticed some odd looking adjustment options.
I was expecting to see an air bypass, idle mixture and vacuum port on both sides. I only have it on one side. Pic below.
The side missing the air bypass happens to be the lowest reading of all 4 carbs, so how do I adjust that one?
Carbs are numbered, 40 IDF 42/43 4C on the base of both.

[Shivers]

Mine are 40’s but mine have the same adjustments on both sides. I’ve never seen
that model. I’d say that you match the one with the adjustment to the one that must be factory set. For what I do not know.

[NARP74]

I was expecting symmetry. I can't find any other examples or documentation for these.

[infraredcalvin]

NM i read the question wrong…

[NARP74]

I pulled one carb off and got some answers, not ones I wanted, but they are answers.
That pipe that looks like a vacuum port, is filled with company epoxy and is not even drilled through on the inside. It's a dead hole. I have no idea what these carbs would be for or how to balance them.
My pump jet was stupid small too. Might explain the dead spot in transition from idle to throttle.
Oh well. If this car was worth it, I would love a modern FI system, but they are too expensive for this old thing.
Every thing I look at tells me it has had a hard 50 years in the world.

[technicalninja]

I have a possible inexpensive route for you.

Look to this thread.
http://www.914world.com/bbs2/index.php?sho...371955&st=0

@MikeK bought some clones that he said came with 28 venturis from the get-go.

The vents are available from Pierce for 100 a set (approx) but MikeK stated his clones cost 150 for the pair!

He goes onto to show internal pics and discuss issues with them on the second page.
Those look pretty good IMO!

That might be a route that needs to be investigated...

[NARP74]

That link is to a utube vid about AFR and engine cooling. I have watched it before, it is worth watching. Is that what you meant?
I also watched a bunch of vw vids trying to figure out these carbs. I saw a bunch of them on the cheap knockoffs, most were happy.

[Superhawk996]

Make sure the idle air bypass screw on the 5 bore is fully closed.

Bring 4.5 / 5 bank up to 6 ish using the adjust screw on the side that affects both throttle bores. Readjust idle mixture as needed.

Alternatively you can bring the bank with 6’s down.

Which way you go depends on where each set of throttle plates are at. You need to ensure the transition ports don’t get uncovered at idle. Example, if bringing 4.5 / 5 back up to 6 is uncovering the transition port, then you must bring the bank of 6’s down.

[930cabman]

Make sure the idle air bypass screw on the 5 bore is fully closed.

Bring 4.5 / 5 bank up to 6 ish using the adjust screw on the side that affects both throttle bores. Readjust idle mixture as needed.

Alternatively you can bring the bank with 6’s down.

Which way you go depends on where each set of throttle plates are at. You need to ensure the transition ports don’t get uncovered at idle. Example, if bringing 4.5 / 5 back up to 6 is uncovering the transition port, then you must bring the bank of 6’s down.

If I recall correctly ( (IMG:style_emoticons/default/blink.gif) ) the Weber folks recommend to bring the high flowing carb down.

And yes, they can be finicky

[MikeK]

Make sure the idle air bypass screw on the 5 bore is fully closed.

Bring 4.5 / 5 bank up to 6 ish using the adjust screw on the side that affects both throttle bores. Readjust idle mixture as needed.

Alternatively you can bring the bank with 6’s down.

Which way you go depends on where each set of throttle plates are at. You need to ensure the transition ports don’t get uncovered at idle. Example, if bringing 4.5 / 5 back up to 6 is uncovering the transition port, then you must bring the bank of 6’s down.

I was thinking along the same lines, though I would consider starting with all the bypass screws fully in. In the picture, it looks like the one you call 5 is out quite a bit more than what I see on mine. With them screwed all the way in, hopefully they settle out at the 4.5 your non-adjustable port is flowing.

My buddy who was looking my knock-off carbs over told me that what he likes to do is flip the carb over and adjust the butterflies so just a small portion of the lower transition hole is visible. Do the exact same to both carbs so you know that they are the same. Install them, then, without balancing via the throttle stop, adjust the bypass screws from fully in to where they are all pulling the same. After they are pulling the same, use the mixture screws to obtain fast idle.

[technicalninja]

Updated my post to reflect CORRECT target.

You've seen the post already as you are the last poster and MikeK has posted in your thread...

MikeK's carbs look like an inexpensive path. His internal pictures look pretty good to me.

Ninja out!

[NARP74]

After a full refresh, not rebuild, the air and numbers are a little better.
1. 7
2. 6
3. 6
4. 7
Got the dwell dialed too.
After having these completely apart, I have decided that they are too far gone for my taste. Too many odd things wrong with them that even a full rebuild would not fix. So I think I have bailed on these.
I do have another engine with a different set of newer Webers that I will start messing with this winter.