dialing in dual carbs

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super-rocker
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dialing in dual carbs

Post by super-rocker »

Hello everyone, I just rebuilt a 2180 engine for my sandrail. I have dual weber 44s on it. I have no idea on how to dial them in. Can anyone help me out with this. The carbs are brand new. Thanks !

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Re: dialing in dual carbs

Post by Glamisbound »

I remember running dual 48's on one of my cars a few years back. I could never get them totally dialed in. And I remember most people had problems either getting them synched or keeping them that way. Good luck.
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Re: dialing in dual carbs

Post by DuneRookie »

I dont have a rail but dont they make air flow meters for that?

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Re: dialing in dual carbs

Post by phx450 »

I had a guy here in phoenix who dialed in my Delartos and they are spot on.

I will look it up for you.
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Re: dialing in dual carbs

Post by crash »

Dual matched flow meters are the easiest way, but it can be done with a single unit by going back and forth. If you don't want to spend the money for the dual meters, or go nearly crazy going back and forth, then take it to a dyno shop.

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Re: dialing in dual carbs

Post by Intelliduner »

Glamisbound wrote:I remember running dual 48's on one of my cars a few years back. I could never get them totally dialed in. And I remember most people had problems either getting them synched or keeping them that way. Good luck.
If those were IDAs then there's not much you can do--they lack the progressive circuitry of the IDFs and are more like light switches, either off or on (which is why they're popular in drag engines).

I used to have a couple different step by step instructions for tuning IDFs that I used on both 40s and 44s I ran on different engines. I'll see if I can find them.

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Re: dialing in dual carbs

Post by Voice »

How to dial in Dual Carbs:
First, get the idle screws in the same place... (back them off then turn 1/4 turn tight for both)
Next, set the air screws to the same place for both carbs... (1 1/4 turn is good starting point)
Next, Put air flow meter on one carb and take reading
Next, put air flow meter on other carb and match other carb reading by adjusting air screw.

Next, Call oldest duner in camp and have him check your work.

Then, do it again and again and again until you can do it by sound like aforementioned oldest duner.

Seriously... if your jets are correct and the carbs are in good shape it's not too tough to adjust the air screws so that they pull evenly by using the airflow meter...

But if you don't know what jets to use or what an air screw is, then find an oldschool guy to help you out or take 'em to a shop to get them dialed in the first time.
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Re: dialing in dual carbs

Post by proglamis »

I guess I'm lucky. I have four motors with dual 44 IDF's. My neighbor is my engine builder and he adjusts the carbs by ear. They all work great.

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Re: dialing in dual carbs

Post by MattV »

My solution was to remove and sell the aforementioned VW engine. I then used the proceeds to buy a fuel injected, water cooled engine and stand alone engine management. I ended up spending for the whole set up about what I originally had in the motor alone. More power and more importantly, no more issues.
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Re: dialing in dual carbs

Post by dirtcrash »

super-rocker, first go pickup a synchrometer (air flow meter) not a uni-syn, then go to aircooled.net, they have a couple of very good instructional articles on jet sizing, and carb balancing. Helped me out a lot when I rebuilt and balanced my and my buddies dual 44 IDFs. Good Luck and be prepared to spend and afternoon or more getting them just right.

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Re: dialing in dual carbs

Post by Woodglue »

Welcome [back] to the board dirtcrash! :wink:
With 2 years, 10 months, 3 weeks and 6 days since your last post on Dec 02, 2005, I'd say you've been lurking for a while! :lol:
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Re: dialing in dual carbs

Post by dirtcrash »

Not lurking, just ended up back in the field running a crew instead of driving a desk where I could keep up on everything. Still a supporting member, and still in the sand, will be poker running this weekend (7 for 7) on a new motor in the wifes rail.




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Re: dialing in dual carbs

Post by Woodglue »

dirtcrash wrote:Still a supporting member
=D>
dirtcrash wrote:still in the sand
=D> =D>
dirtcrash wrote:will be poker running this weekend (7 for 7)
=D> =D> =D>
dirtcrash wrote:on a new motor in the wifes rail
=D> =D> =D> \:D/

It ALL sounds good to me! :wink:
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Re: dialing in dual carbs

Post by fortyeye »

Don't know if anyone is still looking at this topic ... but here goes. Even if your carbs are brand new, there are some things that you should do. Not sure how involved you want to be, but, ALL Webers need to be treated to some basics before you even start. The carbs need to be dis-assembled, cleaned (spotless including the passages where the jets reside) and the float levels set. Your fuel pressure needs to be set to between 2.5 and 3 psi. Without these first steps, jetting and sync will be a chase to overcome incorrect basic settings. If you're still with me, let me know and I'll post some diagrams that will help. Reading and following John's teachings on aircooled.net is excellent advice. He is one of only a few people who really understand Weber setup and tuning.

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