empi 34 duel carb setup

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lockdoc
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empi 34 duel carb setup

Post by lockdoc » Wed Apr 26, 2017 8:35 am

Hey guys, I am new to the site I have a 70's sand rail and I just built my first 1641 vw motor and I am having trouble with the linkage on the carbs it ether to long or to short I have tried all different ways to set it up any input you can give me would be greatly appreciated.

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Piledriver
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Re: empi 34 duel carb setup

Post by Piledriver » Wed Apr 26, 2017 12:59 pm

Pics might help.

Can be uploaded in the "full editor" 800x600, 85% jpeg to limit size works.
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Marc
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Re: empi 34 duel carb setup

Post by Marc » Wed Apr 26, 2017 4:47 pm

Sounds as though you may have a "center-twist" linkage like this one?
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Re: empi 34 duel carb setup

Post by Marc » Wed Apr 26, 2017 5:01 pm

This is SCAT's version of a "universal" center-twist linkage that's marketed for the ICTs, very similar to EMPI/Bugpack's: https://vwparts.aircooled.net/SCAT-Cent ... /30050.htm

Because the 34ICTs aren't "mirrored" carbs, one side needs the linkage to push while the other side pulls. Kadrons are the same way, their linkage uses a single cross-link between the carbs which is moved by a short draglink coming off the center pivoting lever - that keeps the carbs mechanically synchronized throughout the full range of travel.
When two separate rods are attached to a common pivot point, the leverage varies from side to side as the lever swings through its arc. It's not possible to achieve perfect mechanical synchronization but you can come very close IF you set up the linkage so that the center lever is pointing straight forward towards the fan housing when the carbs are at half throttle opening - that's the first thing to establish (you might need a different-length throttle cable to achieve that depending upon the particular center pivot's geometry. Try getting that right and see if you still have issues with the rod lengths.

"Cross-bar" or "hex-bar" linkage setups avoid this issue, although they can still have a little imbalance depending upon the slop at their pivot points on the ends and/or if the bar twists - since the cable arm isn't centered one side is longer than the other and can act differently if things aren't snug & stiff. Personally I use Gene Berg fanshroud-mounted linkage with homemade downlinks for the ICTs - that avoids all the problems but is rather expensive. The cross-bar type is second-best and the center-twist comes in dead last - but it can be made to work. So far as I know, nobody makes a Kadron-style setup for the ICTS but that would work great - dunno how hard it would be to modify the aftermarket Kadron replacement linkage to fit the ICTs but it's an idea worth considering. You'd need to find ball-studs to attach to the carb levers or find outer Heim-joint style ends the right thread to fit the cross-link studs, and the length might be off (that should be easy to change at the point where the two halves of the cross-link bolt together). http://www.shop.kaddieshack.com/NEW-Kad ... 3-4410.htm

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