Type 1 Dual Weber IDF issue

Oct 06, 2004 5 Replies
H

I have been helping a friend with his 67 bug, he's got a 1915 engine with dual 40 IDF weber carbs and the CB performance hex bar linkage. It runs fine, but the gas pedal has virtually no 'resistance'. You barely touch the thing and it wants to just leap out of it's own skin.



I noticed that the entire linkage is being returned to idle by those two pathetic little springs built into the throttle shaft on the carbs. This arrangement just does not provide the amount of resistance necessary to make the car more pleasing to drive. My 74 super 'drives' easier because in stock form it has a stronger return spring.



Does anyone have any recommendations for changing the linkage system so as to provide a better throttle? Is there a stronger return spring kit, or an add-on that anyone is aware of to address this? Anyone have any pictures of what such a kit(if it exists) looks like when installed?



Thanks in advance...



Chris


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D

Oh, I got lots of opinions on the CB hexbar with webers.

1) yes, add helper springs on each side. I got some from Kragen in their misc (help parts) area. Just a simple cheapy chrome bracket and a couple springs. I found those springs to be a bit harsh, but the bracket can mount downwards quite well off the inner corners. I did get some softer springs at a hardware store.

2) progression (or feel) will suck major. The CB hexbar behaves either linearly (except on both edges of travel) or with inverse progression and gives the user an on/off feel at the pedal which when you try your best, you can't help but always do jack-rabbit starts or either stall/wheel spin on hill starts. At least, this was my experience. I solved it by doing two things:

a) re-engineered throttle arm into a wheel to remove its non-linear character. For me and my 44s, radius was solved to be 42mm given 35mm of cable travel:

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b) lengthen the linkage rods to the 5 7/8" ones giving an angle like this:
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By making the linkage rods longer and at such an attack angle, you achieve gaining progression and with the wheel acting linear, the progression is passed to your foot unharmed. You'll like it.

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G

A bit more pricey, but how about the Gene Berg linkage? It's compatible with many different types of dual carb systems; just change out the drop arms to match the type of carbs you have.

Here's an older pic of my setup:

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That's the Berg Linkage with the Kadrons (I have since switched over to Dellortos by getting a set of replacement drop arms to suit the Dellorto setup). It's hard to see in my picture, but there are two sets of reasonably strong springs at the main pivot point in the center. Basically, this linkage setup gives a nice "feedback" at the accelerator pedal.

Geoffe Elias '74 Super Beetle

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J

I always install an extra spring in the linkage somewhere, on both sides. I've noticed the same.

Jan

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M

And you can upgrade the Berg linkage by replacing the joints with real heim joints. Makes an already excellent linkage even better.

Before:

http://66.225.214.60/ghia/MVC-558F.JPG After:

http://66.225.214.60/ghia/MVC-562F.JPGhttp://66.225.214.60/ghia/MVC-563F.JPGhttp://66.225.214.60/ghia/MVC-564F.JPG Max

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G

Hmm...looks like an idea for a new project for me...

Geoffe Elias

-74 Super Beetle

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