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> Carb Bellcrank Equation
damnfiknow
post Dec 28 2010, 09:12 PM
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Someone, please, the equation for determining the diameter of a bellcrank to be used on a Weber 40 setup. Standard 914 accelerator cable length/throw (full close/full open) and standard Weber 40 butterfly. Also, anyone know of a source for such a bellcrank? Hope not to have to farbricate one myself. No lathe so will have to be with an electric drill for turning power. Extremely primitive.
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McMark
post Dec 28 2010, 09:17 PM
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The absolute best bellcrank I've seen is this one from CSP.

It's extremely rugged. Really, really well built. And even uses ball bearings for the rotation. Such a great product and worth every penny.
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biosurfer1
post Dec 28 2010, 10:01 PM
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I have the one Mark pointed out and I like it. It's easy to adjust and will even work if you install it incorrectly...ask me how I know:/
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mrbubblehead
post Dec 28 2010, 11:15 PM
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QUOTE(McMark @ Dec 28 2010, 07:17 PM) *

The absolute best bellcrank I've seen is this one from CSP.

It's extremely rugged. Really, really well built. And even uses ball bearings for the rotation. Such a great product and worth every penny.


do you have any pics of it installed?
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McMark
post Dec 29 2010, 01:10 PM
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I sure do!


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jeffdon
post Dec 29 2010, 01:15 PM
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QUOTE(McMark @ Dec 29 2010, 11:10 AM) *

I sure do!


So in this setup, it appears that both rods link to the carbs at the BACK of the carbs. My carbs are absolutly identical, which means the rod attachments are at the front of one carb, the back of the other. My bell crank is homebrew and designed to accommodate this. I have a hunch that it does not pull equally on both carbs. anyone care to comment on the viability of my set up? Don't hate on the general condition of the rest of the engine bay, I have cleaned it up since i took the pic.


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mrbubblehead
post Dec 29 2010, 01:32 PM
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QUOTE(McMark @ Dec 29 2010, 11:10 AM) *

I sure do!


do you think this is a better setup than the hex linkage from cb performance?
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Mike Bellis
post Dec 29 2010, 02:16 PM
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QUOTE(mrbubblehead @ Dec 29 2010, 11:32 AM) *

QUOTE(McMark @ Dec 29 2010, 11:10 AM) *

I sure do!


do you think this is a better setup than the hex linkage from cb performance?

I had a type 1, full race 1776 that I used to drag race. I had the hex linkage come off many times due to wheel hop. Always at the pivot points. I've never tried this bell crank but I have made my own in the past. I would lean to the bell crank over the hex.
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mrbubblehead
post Dec 29 2010, 02:23 PM
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QUOTE(jeffdon @ Dec 29 2010, 11:15 AM) *

QUOTE(McMark @ Dec 29 2010, 11:10 AM) *

I sure do!


So in this setup, it appears that both rods link to the carbs at the BACK of the carbs. My carbs are absolutly identical, which means the rod attachments are at the front of one carb, the back of the other. My bell crank is homebrew and designed to accommodate this. I have a hunch that it does not pull equally on both carbs. anyone care to comment on the viability of my set up? Don't hate on the general condition of the rest of the engine bay, I have cleaned it up since i took the pic.


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seams like i had a single 4o idf setup on a center mount type 1 offroad car. the carb i had had the throttle pull on the wrong side. FAT performance had the arm to allow me to put it on the other side of the carb so i could use it. but if your linkage is working well, it might not be worth the change.

reread your post. its not working well. call FAT. if i remember right, the arm is different, so you cant move it front to back. but check to make sure. maybe it was the arm on MY carb that wouldnt work.
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SirAndy
post Dec 29 2010, 02:24 PM
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QUOTE(jeffdon @ Dec 29 2010, 11:15 AM) *
My carbs are absolutly identical, which means the rod attachments are at the front of one carb, the back of the other.

Just switch the attachment on one of your carbs so they both attach in the rear ... (IMG:style_emoticons/default/shades.gif)
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ConeDodger
post Dec 29 2010, 02:34 PM
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QUOTE(McMark @ Dec 28 2010, 07:17 PM) *

The absolute best bellcrank I've seen is this one from CSP.

It's extremely rugged. Really, really well built. And even uses ball bearings for the rotation. Such a great product and worth every penny.


Is this what I should be using for my Jenvey's Mr. McMark?
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mrbubblehead
post Dec 29 2010, 02:39 PM
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QUOTE(jeffdon @ Dec 29 2010, 11:15 AM) *

QUOTE(McMark @ Dec 29 2010, 11:10 AM) *

I sure do!


So in this setup, it appears that both rods link to the carbs at the BACK of the carbs. My carbs are absolutly identical, which means the rod attachments are at the front of one carb, the back of the other. My bell crank is homebrew and designed to accommodate this. I have a hunch that it does not pull equally on both carbs. anyone care to comment on the viability of my set up? Don't hate on the general condition of the rest of the engine bay, I have cleaned it up since i took the pic.


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it looks like the parts in the csp link comes with the arms for the carbs so you may not need anything extra (IMG:style_emoticons/default/biggrin.gif)
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anderssj
post Dec 29 2010, 02:43 PM
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QUOTE(McMark @ Dec 28 2010, 11:17 PM) *

The absolute best bellcrank I've seen is this one from CSP.

It's extremely rugged. Really, really well built. And even uses ball bearings for the rotation. Such a great product and worth every penny.


Looks VERY nice!

CSP's web-site says the linkage fits Weber IDFs, but no word on Dellorto DRLAs. I'm thinking that if CB Performance hex linkage fits both, then the CSP should too. Anyone using this on Dell's?

Thanks!

Steve A-
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Cevan
post Dec 29 2010, 03:03 PM
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Let me see if I can remember how I did mine. If I recall, the sweep of the IDF's butterfly is 78 degrees. I measured mine. Then I measured the amount of cable taken up by the gas pedal (with the adjuster at about the mid-way point). The circumference of a pulley needed to pull the right amount of cable is the length of the cable throw divided by (78/360). The radius of the bellcrank or in my case, the pulley is the circumference divided by 2*pi.

So if the gas pedal took up 2 inches of cable, then the circumference is 2/(78/360)=9.2 inches. The radius of the pulley=9.2/2*pi=1.47 inches. So the diameter would be 2.94 inches.

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McMark
post Dec 29 2010, 03:49 PM
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QUOTE(jeffdon @ Dec 29 2010, 11:15 AM) *

I have a hunch that it does not pull equally on both carbs. anyone care to comment on the viability of my set up?

Unequal pulling/pushing is unacceptable. You should be able to adjust your carbs so that they hit WOT at the same time and flow the same volume of air at idle. I'm a fan of home built stuff, but you gotta be 100% accurate with this type of thing or you're engine may not run smoothly or you may be tossing money away in wasted fuel. A carb linkage should have ZERO slop or wobble. It should move both carbs equally, and it should be simple.

QUOTE(mrbubblehead @ Dec 29 2010, 11:32 AM) *

do you think this is a better setup than the hex linkage from cb performance?

100% better. I will NEVER recommend hex linkages again. They are all horrible.

QUOTE(ConeDodger @ Dec 29 2010, 12:34 PM) *

Is this what I should be using for my Jenvey's Mr. McMark?

I think so. (IMG:style_emoticons/default/sunglasses.gif)

QUOTE(anderssj @ Dec 29 2010, 12:43 PM) *

CSP's web-site says the linkage fits Weber IDFs, but no word on Dellorto DRLAs. I'm thinking that if CB Performance hex linkage fits both, then the CSP should too. Anyone using this on Dell's?

It looks like they'll work.
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azbill
post Dec 29 2010, 05:57 PM
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Take a look at the Sidewinder bell crank designed for the Type IV engine. I use this on my Jenvey throttle bodies works perfect. every time all the time Yes I make them and sell them. Check the vendors section.


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914werke
post Sep 12 2019, 05:21 PM
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@mcmark In the example pic you provided it appears the angle of the T-cable comes from the front of the engine rather than the R side like OE?
Did you find its necessary to reroute due to cable length or bracket placement?
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johnhora
post Sep 12 2019, 09:53 PM
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Source for the CSP Mark mentioned...

https://www2.cip1.com/ProductDetails.asp?Pr...129%2D941%2D400

out of stock at the moment but they get more all the time.
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porschetub
post Sep 13 2019, 01:22 AM
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QUOTE(mrbubblehead @ Dec 30 2010, 07:32 AM) *

QUOTE(McMark @ Dec 29 2010, 11:10 AM) *

I sure do!


do you think this is a better setup than the hex linkage from cb performance?


Yes.
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porschetub
post Sep 13 2019, 01:29 AM
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QUOTE(johnhora @ Sep 13 2019, 03:53 PM) *

Source for the CSP Mark mentioned...

https://www2.cip1.com/ProductDetails.asp?Pr...129%2D941%2D400

out of stock at the moment but they get more all the time.

I heard they are no longer being made in the 914 application (IMG:style_emoticons/default/confused24.gif) .
Been searching for a customer for sometime,plenty in the UK but the shipping is mental for me.
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