Dual carb question, Dellorto 40s on a 1.8L to be exact Options

[terrymason]

The problem - The car will go very lean around 2500 rpm, as if the pump jets were too small.

History:
New fuel pump (3.5 PSI to each carb)
55 idle jets
55 pump jets
140 main jets
175 air correctors
These carbs are new to the car, and I'm trying to dial them in.

The car is lean when I first start it (16 / 17 on my air / fuel gauge), but then levels out to a nice 14.7 idle when warmed up. While driving, I can give the car 20% or so of the pedal, and drive up to highway speeds nicely, but when I goose it, it will go very lean (18-22 on my gauge) followed by a series of backfires and loss of power. I started off with 35 pump jets, and have moved up to 55s, which appear to be the most popular around here. I've also adjusted the pump jet linkage, from the nut fully loosened, and moved it in as far as it would go before affecting the main throttle shaft (like 60 turns or something).

What do you guys think, do I need 75 pump jets?

[type11969]

Going back to the first page of this post it looks like the difference between .2s and .3s is the max OD. If you have .1s soldered to match .2s then the OD should be fine (according to the .jpeg).

Are you sure all the idle jet passages and accel pump passages are clear? Do all 4 pump jets "fire" when you twist the throttle? One thing that can happen is that the little ball bearing in the accel pump passage no longer seals on its seat due to accumulated crud, if that happens, pressure in the accel pump passage bleeds off so next time you try to accelerate, nothing gets shot out of them.

60 idles seem really big, maybe you are running too rich and the bog is due to that?

I've never messed with the airs, what do you hope to accomplish by dropping down to 160s? All I know is that 180s are recommended so thats what I stuck with.

-Chris