Weber Carb - enrichening circuit?

I'm talking about the two brass tubes/slugs (whatever they are) under the blanking plate. Enrichment circuits for cold start, or something else?

Here's a picture:

I'm unsure of the question here. Yes, with a blocking plate there's no tabs to hold the tubes down and closed. I got one of mine stuck open once. So I put the enriching circuit on them. Maybe I'll run a choke cable one day...

And maybe before that I'll get my 2270cc Jake Raby motor running again first!

Almost everyone says to discard the enriching circuit and put blocking plates on. What are they thinking that no one ever does a wild downshift and pulls massive vacuum?

/me goes back to lurk mode

Thank you for that, David.

So, the tubes should be down. I'll check to be sure they are. I'd like to lock them closed somewhow.

This IS for a Raby engine that has backfired since day-one.

:) Many years ago I had a Yamaha GP road racer (one of Gary Nixon's bikes), and it had a trigger by the throttle that pulled the enrichening circuits on. It was intended to let the rider stream fuel (pre-mixed oil and gas) during a drag down at zero throttle.

Doh! It took me almost a week to to get to the bottom of that for me.

I'm not fully sure down is the correct off direction for the tubes, but hopefully should be obvious. If all else fails, with the covers off on both sides, put your hand over them to find the one pulling air.

I'm saving for LN nickies as I got water in my engine and it wrecked it bad. Maybe one day when I'm made of money, but not in my current situation, today :(

I have the first set of nickies. The engine runs way much cooler.

Toss the blockoff plates, put the cable mount plate on it. I just did quick look and can't even find a part number for it, or even a picture. Maybe this helps:

Wow, seems everyone in the world goes choke-less. I'll post a pic of mine when I get a chance. I don't recall where I bought them. Any local hotrod carb place should know where to get a pair. They probably have a box of them labeled "junk".

I have extreme envy :)