OK so don't shoot me down right away but I have spent a good bit of time looking at the various types of bell crank linkage that are out there. To me, the ones with solid push/pull rods are very expensive and have inherent limitations. With the solid rod I would think that you have more areas (push and pull) where the requirement to make adjustments could impact the performance. I have seen some cables systems that eliminate the solid rods, but are still expensive.

I think I have a way to use off the shelf parts to make a cable linkage for just over $50. I was wondering if that had any appeal? It seems that using cables would have an advantage over using rods in that you only had to adjust the pull direction. You reduce the need for adjustment hardware 1/2 and cables are not subject to being bent when performing work on the car and are less likely be a source of adjustment headaches.

Thoughts?

You can, but it takes a good deal of devlopment.

That is true on the development. But I am only looking to take what is known and change a few items to bring the cost down. I worked in a research and development role for a number of years and had to give up on a number of great ideas that turned out to not be viable.

I currently have a number of requests out to source most of the parts. I certainly view this as something that the ultra high performance people would not want but the middle ground seems to have some potential.

I made my own cable pulley linkage system. I had to mock it up with my carbs off the car. It wasn't that hard and I am no engineer. I probably have 50 bucks and 10 hours in it. Click to view attachment Click to view attachment

That is a pretty cool approach! That is the approach that I like. The existing options are great. But to costly for the majority of people to take a chance on.

I saw the pull mount to the carb and I assume you used a direct pull approach rather than a bell crank?

The cable linkage is an excellent way to go, used on BMW motorcycles for about a million years now. If you want some background that might speed the process check out what other people have done, like HERE. Works great, best linkage available. Problem is the $300 price, but worthwhile to know about for the background.

If you get to the part where you need nuts and bolds talk with the people at Pierce Manifolds (HERE).. They're Weber specialists, good, interested, helpful, and have so many oddball linkage parts in stock they might be able to cobble things together from their parts bins. Here's their advertized liinkage parts page, (Popular Linkage Bits). They have ten times more stuff on the shelf than what they advertize. Check out some of their car photos and imagine syncing four IDF's instead of two.

Another guy to talk with would be Art Thraen at ACE in Salt Lake City. He's good, his shop is all-aircooled, speicalizes in carburetion, and could probably speed the process considerably.

Lastly, if you want an indication of interest, check out how people here reacted when Jake Raby announced he was going to sell the cable linkage developed by Pete in theSamba thread: HERE. Obviously there's a lot of interest in something better, but the interest drops off a lot after about $200. It isn't a large market, but if you can do better I'd say you'll sell them.

The linkage from Tangerine Racing works on 914's. I don't think one on the Samba does.

I think that's actually the same system, made by the same guy. Raby sold it too. A couple of years ago Slowtwitch said he'd had inquiries from this board and had one in the works for 914's. I hadn't seen anything since, but easy enough to check with him, or with Chris at Tangerine. That's if you want a more expensive off-the-shelf system, but Mike is talking about developing his own, so it was mentioned really just for background and reference.

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I was one of the guys asking SlowTwitch if he was going to make a 914 compatible setup but I never did get an affirmative response.

Chris could clarify this but I believe his setup uses his own components. I've had a cable linkage on my car for over 3 years and it just works. I usually check the sync of the carbs at the beginning of the year and just forget about. Never goes out of sync. Carbs open at precisely the same time and at the same rate.

The hex linkages are just archaic IMHO.

The Tangerine linkage is made by Chris, specifically for 914s. I actually managed to get my hex bar setup properly, and it worked well for a few years, but the bar and end links just plain wore out, because theyre cheap and crappy quality.

I've had chris' linkage on my car for over a year, and its a daily driver. While it may be expensive, i view it as an investment in the drivability of my car. Believe me, im one of the cheapest guys on this forum, and i opted to pony up for the linkage..best decision ever.

Btw, i have a philosophy for justifying the price of a car part.. if i can make it for a lot less, with similar quality, i'll make it. however, if someone else has a pretty much bolt on kit, that has a reasonable cost for what it includes, it often times more economical to just buy it, and not waste the time and money doing something over and over because I'm not happy with the quality and operation of it.

The Raby\Slowtwitch product was adapted from the Bug kit. It was never finshed for the 914.

I am running the Tangerine parts on my car.

IMO neither were fully developed for production. The Raby kit by definition from him, and the Tangerine kit has it's hokey points as well.

Either would be better than a hex bar, but I expected more for $200 + each.

Cool. I mention those other threads mostly because of the patent issues for anyone thinking of making htem. In The Samba thread on June 25, 2009 Slowtwitch mentioned that his system was patent pending. He showed that same system first back in 2007, IN THIS THREAD on ShopTalk. Then on October 1, 2009 in THIS THREAD Jake Raby also mentioned he'd developed one that was "patent pending," that day (technically not possible). I'm dubious of the patent claims, because that linkage isn't much different than what's on most current BMW motorcycles, and I saw older-style BMW motorcycle cable linkage on dual-carb VW's at Pismo Beach back in the '70's (something like the one-to-two cable setup you showed in that thread, Chris). In any case anyone thinking of making similar linkage for dual carb boxer motors should be aware of the patent claims. Like I said, I doubt that linkage could be patented, and if Tangerine hasn't had any problems then there probably won't be any, either. Only that.

Yes. At $50-$75 ill get one all day long.

One of the problems in these systems is the changes caused in the linkage by thermal expansion and vibration. Of course these are the exact things that engines are so good at producing. As it seems to be apparent that cable systems seem better at coping with these problems than any of the solid linkages, I think that any solution should be cable based. Additionally, solid linkages are much more prone to damage than a cable system when you are performing maintenance.

As shown in Jakes model and others, the pull mounting systems that are associated with cables are not very attractive. Thanks to the input from all of you I am getting a lot of data to consider in this. But my basic goal is to come up with a system that is adjustable enough to span a wide range of vehicles, uses cable in a way that they don't require mounting to the carb to pull, and target the $50 - $70 price range.

I am in no way thinking that I will or do I intent to make money from this but the problem intrigues me. So while I am far from coming up with a workable design, the feedback is much appreciated. Keep it coming.

the hex bars with the ends loaded with springs doesn't help either. for fans of the hex bar style the Triad system doesn't use springs. you adj and set the linkage side travel with a bolt and jam nut. unfortunately they don't come with any instructions. once you figure it out it's simple.

Yes I used the stock throttle cable with a short adjustable link directly to the passenger side carb. I did re route the stock cable through the engine tin. It now comes up more in the center of the engine bay rather than under the battery. If you look at the picture you can see how I have the stock and secondary cables attached to the same pulley on the first carb in line. The stock cable is on top and the secondary comes off the bottom. It is very efficient.
The only thing I would do differently is use aluminum pulleys next time. All I could find online we're steel and pretty heavy. I did the mock up with plastic ones from Home Depot but I knew that wouldn't last. I drove it around like that for a few days.
I can take some better pictures if you really want to give it a go.

Eric

I am evaluating all options so any additional pictures would be great. What I am hoping to do is not have pulleys. Of course with the linear action from the bell crank it is difficult to translate that into the rotational action that is related to the throttle.

My current plan is to evaluate establishing an anchor point for the cables that is lower than the throttle linkage so that the linear action is transformed into a downward motion that more closely resembles the rotation of the throttle.

This reduces the need for adding things to the carb like braces and pulleys and hopefully let's the carbs maintain their appearance. So essentially it becomes a problem of solving the geometry problem using anchor points that are lower than the carbs and determining if a different lever for the attachment of the cable to the carb is needed.

There are cars that use cable linkages on carburetors, including Webers. And look at some motorcycle carburetors, they all have roller type cable attachements. And give Pierce Manifolds a call, talk with them. I know there are applications that use Dellorto or Weber carbs on Harleys, for example, and there may already be off-the-shelf components available to adapt those carbs to use cables. Save yourself a LOT of time.