Webers and Sychronicity

[JJDraper]

Following the recent discussion on the Hypo tubes etc I decided to work through the simple stuff to try and improve low speed pickup and running. Wide Open Throttle is all very well, but not so easy in city traffic. I have started with checking the balance of the carbs. I had always done this by ear, but had never really considered that individual chokes may be out on the same carb. So, I took the plunge and bought a meter & adapter to get at the tricky ones (3&4). The results were surprising, but satisfying. All spot on! However, until you measure you can't be sure. Easy enough to do and clears up uncertainty in a trice. The angled adaptor seemed ridiculously expensive for what it is - still, its a captive market..

The results shown are with an engine at running temp, but at 750rpm idle.

Next stage is to get the dizzy checked over.

Jeremy
PS yes I know its boring, but sometimes boring helps

[twincamman]

BUT ' boring is where the extra horse power hides ----ed

[frearther]

Jeremy,

What meter did you use?

Art

[Allison]

Jeremy,
hi, that's interesting as I am suffering from the car surging or hunting after having the carbs overhauled; mpg is poor and the exhaust chucks out enough soot to blacken the rear end. However acceleration is excellent and there's none of those flat spots. I've used the old fashioned balancing act of shorting out 1 plug in turn and checking that the fall in revs is the same for all plugs. Next was to check the idle screws, then I reduced the main jets to 115 from 125. That improved things but didn't solve. I've just changed the idle jets from 55 to 45 and see what that does. You've probably read the online articles just as I have and it seems there's a slow and steady period of trial and error! Not sure if I'm in the trial or the error phase!
One thing that confuses me is that the air correction jets are 220 yet the articles suggest they should be mains +50 so 165/175 and I should be furiously lean but the opposite is true!
If anyone has the answer I'd be grateful to hear it!
Peter

[simonknee]

Jeremy,

Check the balance at something a bit higher than 750rpm. When you are running in city traffic you are probably at 1500-2500rpm a lot of the time so check out the balance at these higher rpm. Ideally find a way to press the accelerator pedal rather than twisting out the idle speed screw. It may pay dividends to have the best synchronicity at an rpm you actually drive at.

Simon

[JJDraper]

The meter I use is readily available, although the price seems to be hugely variable. Ebay is not always the cheapest!

http://www.ebay.co.uk/itm/Carb-Carburet ... 168wt_1065

http://www.burtonpower.com/weber-carb-s ... 1-000.html

It seems to be made in Germany and is branded STE. The 90degree adapter cost nearly as much as the unit! The unit is so easy to use, there was a sense of 'Oh, is that all there is to it?'

I tried again with idle set at 1500 (annoying the neighbours).. Still pretty close, so I feel I can put the balancing issue to bed for the moment.

Jeremy

[JJDraper]

Looking at the carbs in more detail, I noticed play on the Choke assembly. If this normal?? I have nothing to compare it with! I have never used the choke in over ten years and wonder if the whole gubbins can be blanked off as this must be a potential area for air/petrol leaks.

I tried to capture the movement in a short video clip..

http://www.youtube.com/watch?v=BuLSWvxxh7I

Any thoughts?

Jeremy

[holywood3645]

In last months Classic Ford mag 'New Products' there is a Choke delete Kit advertized for Weber sidedrafts. I will check when i get home an PM you the details.
James