81 GS1100G Carb Syncronization

[Brendan W]

Nice one.
Can you get your Goldfish to swim synchronised?

[Nessism]

Those aquarium restrictors will work, but be sure to calibrate them on one cylinder, so they will all be the same.

[Who Dat?]

The service manual describes the use of a bar gauge setup with increments but not "Hg values, and that the inner cylinders are to be set differently than the outers. Does anyone know what this difference would translate to in "Hg?

The service manual shows carb sync with the special Suzuki tool that uses four balls. The inner cylinders were to be set about half a ball lower than the outer ones. I seem to remember someone testing that and found that "half a ball" was the same as 2cm of Mercury.

Keep in mind that nobody really knows why the inner cylinders are to be set differently. that is something that started in 1980, which is also when the CV carbs started, along with a balance tube between exhaust pipes 2 and 3. Mostly, most of us just set them all the same and can't really tell the difference.

Values? Forget them. As others have said, equality is more important than values.

[Rijko]

I disagree...

Keep in mind that nobody really knows why the inner cylinders are to be set differently.

The reason is known : this is because of the scavenging effect caused by the balancing pipes on standard exhausts.
On a GS1000 with a 4-in-1, the carbs should be synced the same height since no balance pipes/scavenging effect.

That is something that started in 1980, which is also when the CV carbs started, along with a balance tube between exhaust pipes 2 and 3.

Actually, the balance pipes started with the first model GS1000, so the sync procedure also applies to the models with VM carbs.
It is in the GS1000 manual for those bikes.

Mostly, most of us just set them all the same and can't really tell the difference.

Doing this on a GS1000 with standard exhausts WILL cause a machine running noticably sub-par.
So much so that, when i made this mistake, i turned back within a few km into the testdrive and corrected the problem.

[Supercub]

I can make restrictors on a lathe to fit the ID of the tube, would a 1/64" hole be enough to provide a steady reading?

[Rijko]

Try it.

Afaik 1 mm is too big, but you're at approx 0.04mm at 1/64" so that may work.

[Supercub]

So set the middle two 2cm or .8" lower?