weber balancing

[red67]

i got inspired very recently.
i'd really love to learn how to balance the carbs myself.
i know well oiled pros can do it by sound alone!, but what does the average non-pro joe need in his arsenal to do it? (previously all i've done is lean out a rich cylinder that was sooting it's plug, with a quarter turn on the air screw with no metering)

what meters/sensors do i require?

many thx in advance.

[edmayo]

The only real tool you need is a synchrometer, but after that there is a definite procedure you need to follow, are you familiar with what that is?

[mjmoran]

A basic step by step procedure can be had from PMO. Also, the weber tune manual is handy as well. A unisyn or other sync device, a small 3cc vial on a wire and a float level guage are the real tools of the trade. Not too big a deal if you are a patient type...

[jameshtaylor]

I have no direct experience but a respected commentator on another list said JCWhitney makes one of the better synchronizers around for a modest $30. See their web site, part number ZX882792N. JHTaylor

[911pcars]

I've used a Gunson CO meter to make fine adjustments of the idle mixture. A very slight adjustment of the six screws changes the mixture from 4% -> 3% CO.

FWIW,
Sherwood

[red67]

thanks guys. much appreciated.
i told a friend at the weekend and he handed me a unisyn.

i'm not aware of the preocedure but pete zimmermann off rennlist said he'd take me through it step by step. so wish me luck! quite excited to take it on. i love learning these things.
theres a photo on here somewhere with all the parts of the webers listed and labelled in color but i cant remember where i found it... anyone remember what i'm referring too?

[Bruce M]

The unisync type gauge does the job.

However, it is tricky. The top (air flow restricter) has to be set carefully and not changed between cylinders.
It is very easy to knock the gauge and change the setting.

I would recommend buying/borrowing a scroll type gauge.
I bought one at a car show a few years ago and have used it a number of times. It will always give consistent measurement as there is nothing to set or change.

In fact, before I bought the scroll gauge. I got fed up using the unisync style and used a rev-drop technique.

To do this, set the idle at say 1200rpm then disconnect each HT lead in turn and check the reduced rpm. adjustments are then made to make this even for each cylinder (bigger drop means cylinder is contributing more. therefore reduce idle setting on that cylinder). Finally, carefully reduce the idle with even adjustments. This can also be repeated at say 2500rpm to check linkage geometry. please note, some rev counters cannot handle this technique.

I found this easier and more acurate than the cheaper gauge.

BTW. always check the timing first. It is a pain if you carefully set the idle then change the timing and it goes off!

[jameshtaylor]

What is a "scroll type gauge"? Who makes these things? Thanks,
jim taylor

[edmayo]

It's also referred to as a synchrometer, and you can get one from PMO, Performance Products, and Stoddards, and probably a million other places.