Author Topic: Throttle linkage - TC Dellorto carbs  (Read 675 times)

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Offline RafM

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Throttle linkage - TC Dellorto carbs
« on: Tuesday,July 13, 2021, 04:07:13 AM »
TC with twin dellorto carbs - Would anyone have a reasonably close up photo of the throttle cable connection to the carb linkage? I'm in the process of connecting everything up, the cable does not seem to have enough travel to open the carbs fully, the return spring is correct but is too thick to fit through the linkage hole, among other things! thanks.

Offline EuropaTC

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Re: Throttle linkage - TC Dellorto carbs
« Reply #1 on: Tuesday,July 13, 2021, 08:07:05 AM »
Are you sure you've not got a Weber spring ? IIRC the weber return spring is thicker & stronger than the dellorto one or at least the one on the Elan (Webers) is heavier than the Europa on Dellortos.

Brian

Offline RafM

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Re: Throttle linkage - TC Dellorto carbs
« Reply #2 on: Tuesday,July 13, 2021, 10:00:28 AM »
Are you sure you've not got a Weber spring ? IIRC the weber return spring is thicker & stronger than the dellorto one or at least the one on the Elan (Webers) is heavier than the Europa on Dellortos.

Brian

Hi Brian,

Could be, I did specifically order a dellorto one but seems to be a bit of a lottery. The spring fits ok, I have drilled the hole out slightly on the linkage, I wanted to check exactly how the cable attached, mine seems to be a bit jerky at the moment. Raf.

Offline europa88

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Re: Throttle linkage - TC Dellorto carbs
« Reply #3 on: Tuesday,July 13, 2021, 11:36:42 AM »
TC with twin dellorto carbs - Would anyone have a reasonably close up photo of the throttle cable connection to the carb linkage? I'm in the process of connecting everything up, the cable does not seem to have enough travel to open the carbs fully, the return spring is correct but is too thick to fit through the linkage hole, among other things! thanks.

Is this any help?
If you no longer go for a gap that exists, you are no longer a racing driver.

Offline RafM

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Re: Throttle linkage - TC Dellorto carbs
« Reply #4 on: Tuesday,July 13, 2021, 02:51:43 PM »
TC with twin dellorto carbs - Would anyone have a reasonably close up photo of the throttle cable connection to the carb linkage? I'm in the process of connecting everything up, the cable does not seem to have enough travel to open the carbs fully, the return spring is correct but is too thick to fit through the linkage hole, among other things! thanks.

Is this any help?

Yes, that's great, thanks, Raf.

Offline RafM

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Re: Throttle linkage - TC Dellorto carbs
« Reply #5 on: Wednesday,July 14, 2021, 05:50:27 AM »
At the moment my throttle cable is connected from above the carbs with the inner cable attached to the bracket on the air-box. When the throttle is pressed the outer cable sleeve is dragging the linkage open. I'm going to drill out the hole in the air box bracket and feed the cable up from below, which seems like a better set-up as the inner cable does all the moving.  I have searched on-line and seen both options used, also different return spring set-ups. I guess it's the usual route of trying out options until you find what works best.

I've also seen this twin cable set-up but not sure about the twin cables running back and connecting to the pedal assembly.

https://classiccarbs.co.uk/product/dellorto-dhla-twin-carburettors-throttle-linkage-kit-twins-triples

Any opinions gratefully received, Raf.

Offline Roger

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Re: Throttle linkage - TC Dellorto carbs
« Reply #6 on: Wednesday,July 14, 2021, 06:41:46 AM »
Pushing down with the outer works perfectly well, and it's designed that way.
Trouble is, many people don't understand  it and  " improve" it!

Offline EuropaTC

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Re: Throttle linkage - TC Dellorto carbs
« Reply #7 on: Wednesday,July 14, 2021, 09:22:21 AM »
At the moment my throttle cable is connected from above the carbs with the inner cable attached to the bracket on the air-box.

And

I've also seen this twin cable set-up but not sure about the twin cables running back and connecting to the pedal assembly.

https://classiccarbs.co.uk/product/dellorto-dhla-twin-carburettors-throttle-linkage-kit-twins-triples

On the first point, the Elan set-up with webers works in the same way with the cable above. I suspect the reason why the Europa is "reversed" is because the cable comes out of the cabin below the level of the carbs and so a top entry fitment would mean a longer cable and more bends. That might be why yours isn't so smooth, but it's a guess.

On the Elan the cable comes out and loops neatly in an arc to feed in above the linkage.

On the second point, that set-up looks very much like the one BDA has on his engine. It's probably a different make but the principles look similar.

Brian

Offline RafM

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Re: Throttle linkage - TC Dellorto carbs
« Reply #8 on: Wednesday,July 14, 2021, 09:28:25 AM »
Pushing down with the outer works perfectly well, and it's designed that way.
Trouble is, many people don't understand  it and  " improve" it!

I understand. However, now that I have changed the cable to run from underneath, the throttle action is much smoother and with
less force needed on the pedal.

Offline RafM

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Re: Throttle linkage - TC Dellorto carbs
« Reply #9 on: Wednesday,July 14, 2021, 09:33:47 AM »
At the moment my throttle cable is connected from above the carbs with the inner cable attached to the bracket on the air-box.

And

I've also seen this twin cable set-up but not sure about the twin cables running back and connecting to the pedal assembly.

https://classiccarbs.co.uk/product/dellorto-dhla-twin-carburettors-throttle-linkage-kit-twins-triples

On the first point, the Elan set-up with webers works in the same way with the cable above. I suspect the reason why the Europa is "reversed" is because the cable comes out of the cabin below the level of the carbs and so a top entry fitment would mean a longer cable and more bends. That might be why yours isn't so smooth, but it's a guess.

On the Elan the cable comes out and loops neatly in an arc to feed in above the linkage.

On the second point, that set-up looks very much like the one BDA has on his engine. It's probably a different make but the principles look similar.

Brian

Hi Brian,

That was partly my reasoning to run it from below, less bends in the cable. Now it's done everything is running much more smoothly.

 Raf.

Online BDA

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Re: Throttle linkage - TC Dellorto carbs
« Reply #10 on: Wednesday,July 14, 2021, 09:35:34 AM »
I think Brian is correct. The linkage that RafM linked to is similar in design and function to mine. Since he mentioned my linkage, if someone wants a picture of my setup, here is one.
« Last Edit: Wednesday,July 14, 2021, 12:40:38 PM by BDA »

Offline RafM

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Re: Throttle linkage - TC Dellorto carbs
« Reply #11 on: Wednesday,July 14, 2021, 11:19:56 AM »
I think Brian is correct. The linkage that RafM linked to is similar in design and function to mine. Since he mentioned my linkage, if someone wants a picture of my setup, here is one.

Brian,

I've got my working ok now, after making a few mods and re-routing the cable under the carbs. I am thinking of a set-up similar to yours, especially as it's operated by a single cable.
A better solution all round, nice accurate rose joint adjustment and a better return spring system. The original is pretty agricultural.

Raf.

Offline europa88

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Re: Throttle linkage - TC Dellorto carbs
« Reply #12 on: Wednesday,July 14, 2021, 04:14:56 PM »
Pushing down with the outer works perfectly well, and it's designed that way.
Trouble is, many people don't understand  it and  " improve" it!

Mine has always come up from under the carbs and I've never had any trouble from it in over 40 years  ;)
If you no longer go for a gap that exists, you are no longer a racing driver.