Carb balance issue

[MagicWagon]

I have a 2.0l air-cooled with twin Solex carbs. I just replaced some iffy hoses, including on the balance pipe and thought I'd check carb balance at the same time. I got them reading the same at idle (around 10 on my meter), but if I check again when revving a bit, the left reads a lot higher, but the right barely moved from 10. The linkages seem to move in sync and operate the spindles. What could cause that ? The only difference I see is that the left one squirts fuel via an L shaped tube down into the carb, whereas this is missing on the right carb, and fuel is sqirted across the barrel and sucked in. The van runs ok and will do 60/65+, but can't help thinking it would run even better or more economically if the carbs were better balanced.

[Robsey]

If it sounds and runs well, then I would not worry.

I am sure you have seen Sarran's video on
Youtube.

https://m.youtube.com/watch?v=najLc9GlLJ0

[sarran1955]

Hello,

Couldn't resist...

Here is a more recent video on the same topic...



How much does yor van weigh..and what is your mpg??

Air-Cooled Bliss..

Cordialement..


 

[Rosie n' Jim]

Try this if you prefer words to videos. It explains the idle and fast running ballance technique.  https://itinerant-air-cooled.com/viewtopic.php?t=7767

[Robsey]

Wow!!

That is quite intense and wordy.
Definitely something you should print out, and then read through it many times.
And make notes to clarify things to yourself.

Otherwise there's a good chance that so much writing will just scare the jeebus out of you.

[Rosie n' Jim]

It is rather long, but if it's only ballance that's an issue,it's not too bad. I wrote one line prompts to keep me following the correct sequence. 

[ajsimmo]

From your initial description the thing that leapt out at me was that you balanced idle first, then checked at revs. This is the wrong way round. What matters most is air flow balance at revs. I use a pair of vice grips to hold the throttle cross bar at 2500-3000 rpm, then check/adjust balance. Once that's right, adjust idle at the stops, then the mixture screws and finally the third carb/idle circuit. Done.

Sent from my moto g(30) using Tapatalk

[Rosie n' Jim]

The correct sequence is the key. 

[tobydog]

It helps to check the opening of both carbs from closed to be synchronised. Makes for a smoother pickup from standstill.

[MagicWagon]

Thank you all for the replies. My wife is away in the van at the moment. Seems obvious now I've been told, that the balance at revs is more important and should be done first. I will be following the video and/or instructions once the van is back and I have a spare hour or two.
Regarding the itinerant Aircooled website, it says it's specifically for 1972-1974 vans, and doesn't seem to mention T25's at all. Is there likely to be any difference when applied to our vans ?

[Rosie n' Jim]

Yes, small differences. The air filter and throttle linkage most obviously, but also some piping. For the mixture reference hose use the vacuum retard pipe. That's the one that enters the distributor from the left. It should come from the ldle ballance tube if fitted correctly.
 

[Rosie n' Jim]

Oh, and they have solid valve lifters, so skip that part!