YO! Brosky!!! [RE: Throttle linkage couplings]

[DrEntropy]

Paul! I've been mullin' over the solid coupling thingie for a bit. I have some small aluminum U-joints left over from the days when potentiometers were used in vacuum tube radios... got me thinking: would a small u-joint have benefit in the application? I started bashin' around and came up with this:

https://www.grainger.com Grainger Item #1L730 (LOVEJOY, D2)

The aluminum ones may be too subject to wear, but THOSE steel ones are certainly strong enuff. Alignment would still be an issue, but not as much as with solids, IMO. You would need to drill/tap for grub screws too, but it may get you where you want to be with regard to eliminating the wobbly clips.

...just thinkin' out loud.

 

[Guest]

I am certainly no engineer but I can look at something and usually figure out why it might not work. That comes from being a mouth-mechanic.

It seems to me that a flexible U-joint would allow two shafts that approach from other than a 180* angle to function without binding. Or the bind would be taken up in the joint. However, when two shafts approach straight-on, but on a different plane, you would need a double joint to accomplish this.

Am I wrong?

 

[Guest]

I still think that loosening up everything up (carbs, manifold) and using that slack that all adds up, approximate the shafts as close to perfect as possible then use the light-duty springy joints to do their thing.

The whole idea of a manifold being in three pieces makes for a lot of wailing and gnashing of teeth. (here's that tooth thing again)

What do those out there that run triple Webers do? Aren't those individual manifolds?

 

[DrEntropy]

Not wrong, Bill. Paul has 'em lined up nearly "perfect" and the bit of slop in the u-joint, while not being so much as to cause a "lag" in the shafts on application, may be enough to keep the whole affair (as an assembly) from binding thru the travel.

as I said: just mumblin' some thoughts out loud. /bcforum/images/%%GRAEMLIN_URL%%/smirk.gif

 

[DrEntropy]

Multiple Webers are usually controlled by an externally mounted long shaft and a bell-crank link (adjustable) to each individual throttle shaft.

 

[kodanja]

Multiple Webers are usually controlled by an externally mounted long shaft and a bell-crank link (adjustable) to each individual throttle shaft.

 

[DrEntropy]

push-me-pull-you!! /bcforum/images/%%GRAEMLIN_URL%%/laugh.gif


Sometimes there are variants:

 

[kodanja]

Noice!

 

[Brosky]

Bill, you are 100% correct. I know what I'm doing and I had one heck of a time getting these to work. I finally ended up with the folded couplers that Jeff sent with the solids, but they are twice the thickness of the stock units. I worked my butt off just to try to prove a certain friend of mine wrong, but I failed to do so, because it is just not possible at this time and with this theory.

I'm not totally sold on these stiff ones, so the box from TRF just arrived with new stock folded couplers, along with a few other essential items that I needed.

One day, when it's rainy some Saturday and I have nothing better to do, the center carb will come off again and these will go on.

As I said earlier, my stock twins are aligned perfectly across the center line, but the bell crank sits about 1/8" behind them. They never had any binding issues, so the originals will work OK.

Which, I might add, is exactly what TR6 Bill said at the beginning of my installation. Give credit where credit is due.

 

[jessebogan]

Man, I used to hate setting up Weber linkage. I finally convinced the local BAP GEON (remember when they were the weber distributors Doc??)guys to order me hex rods, and heim joints to suit. No more slippage!! I think I have one rod left somewheres, so I guess I can do one more conversion....

 

[Brosky]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:] but it may get you where you want to be with regard to eliminating the wobbly clips.[/QUOTE]

Doc,

To be honest, my original setup was never wobbly and I always had full throttle. Well, let's say after I got the original carbs back from TRF rebuilding 3 years ago with the new shafts and I aligned and tweaked them, there was full throttle and no binding.

So I don't think that the originals are all that bad.

The solid idea would be great on a one piece manifold. However, since there is none available, we make do with what we have.

The u-joints may still have a bind, depending on the direction of the misalignment after heat up or cool down.

I think that it was a great learning experience and I'm not sorry that I tried to make it work.

 

[DNK]

BAP GEON (remember when they were the weber distributors Doc??)

Gude drive ??? I can see it ,but the location is fuzzy

Man that was a long time ago

 

[DrEntropy]

I remember it like it was yesterday.
~my~ problem is REMEMBERING yesterday. /bcforum/images/%%GRAEMLIN_URL%%/smirk.gif

 

[GregW]

Hi Doc,
I agree with TR6Bill’s double u-joint assessment. There are two drawbacks to the doubles that I encountered.
One is; they are quite long, 5” or more. I went with the smallest I thought I could get away with, but the throttle shaft was too big. Instead of boring the u-joint out (and loosing bite for the grub screw) I lathed the throttle shafts down to fit.

Two; the Lovejoy joints I used did not seem to be designed for back and forth motion. There is a little slop that can add up at each flex joint. So the farther you get from the pedal linkage, the later the carb is on opening. What I came up with was pre-tensioning the joints as I tightened the grub screws and let the carb’s throttle return springs deal with the slop on deceleration.

 

[DrEntropy]

I have no argy with Bill's logic, he's correct. My suggestion comes from the point that Paul had already got the shafts well lined up (since they seemed to be working as one long unit) already. As I said earlier; the slop in the UJ was what I thought would keep the shafts from binding regardless of temp changes and still be fairly acceptable as far as 'lag'. Your "front loading" of the slop makes good sense as well.

I don't remember if the throttle actuator is on the center carb? That would keep the lag equal on both the outer ones, therefore be compensated for as you have done.

I guess this is all moot anyhow, as the spring clips are pro'lly the best answer.

 

[Brosky]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:] I guess this is all moot anyhow, as the spring clips are pro'lly the best answer.[/QUOTE]

For now, that is. Get enough people thinking about the design and you never know what might be better next year. Maybe a high temp plastic, like Peek or Torlon, machined in the solid model?