carb synch adapters

[biker bitch]

Hi all. My question is...where do I attach the carb synchronizer?
The location I was shown is a screw right past the intake boots on the engine.
But I ordered a carb sych adapter for 79 GS 425 and it is about half the width of that screw.
Is there another spot on the carb that I don't know about?
I want to make sure it's wrong before I send it back.

Thanks.
Lena

[countrycummins99]

adding

also to add to her question does anyone know the actual measurment in IN/HG that the carbs are supposed to pull when running correctly?

[tkent02]

Some engines the port is on the intake boot itself, on some it's on the intake port part of the head.
How much vacuum doesn't matter at all, just that they are balanced.

[countrycummins99]

but is it better to aj=djust them to a higher or lower number if their not equal?

Some engines the port is on the intake boot itself, on some it's on the intake port part of the head.
How much vacuum doesn't matter at all, just that they are balanced.

[Steve]

but is it better to aj=djust them to a higher or lower number if their not equal?

It won't matter, you can't adjust them "higher or lower".

You can only adjust them so they are balanced.

Whether they happen to be "higher or lower" is irrelevant.

The carbs have to be open a certain amount to provide enough mixture for the engine to run. One carb is pushed open by the idle speed screw. In Lena's case, that is the right carb, #2. In your case, cummins, it is also the right carb, but you have two-barrel carbs. There is a screw between the carbs that will adjust how much the left carb is opened. As you open or close the left carb, the vacuum level will drop or rise, respectively. When that vacuum level matches the level of the other carb, lock that screw into position, you are done.

For those with other four-cylinder bikes (yours is the only one with the two-barrel carbs), the process has to be repeated, as there are a total of three sync screws that need to be adjusted.

.

[biker bitch]

Some engines the port is on the intake boot itself, on some it's on the intake port part of the head.
How much vacuum doesn't matter at all, just that they are balanced.

Thanks for the quick response. Much appreciated.

[BassCliff]

Greetings and Salutations!!

Hi Ms. biker bitch,

You will find carb synchronization procedures in the links below. If you are here you probably have a 30 year old motorcycle that needs about 20 years worth of maintenance. In the links below you'll find maintenance lists, documentation, wiring diagrams, "how to" guides, vendor links, tips, tricks, and a whole lot of GS goodness. This is your "mega-welcome". Let's get started.

Let me dump a TON of information on you and share some GS lovin'.

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. This is what NOT to do: Top 10 Newbie Mistakes. Now let me roll out the welcome mat for you...



Please Click Here For Your Mega-Welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

More links to helpful threads in the forum:
Help! Your Bike Won't Start
DON'T DO THESE THINGS
Help! Your Bike Won't Run Well
Oh God! Pods!


Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[biker bitch]

This is what my carb synch looks like. Anyone know why the ones in the tutorials look so different?

[Steve]

This is what my carb synch looks like. Anyone know why the ones in the tutorials look so different?

For pretty much the same reason that Cadillacs don't look like Toyotas.

You have a different product from a different manufacturer that happens to do the same job.

What you have will work, but you will have to take an extra step every time you hook them up.
The first thing you will need to do is to connect both gauges to the same carb at the same time by using a "T" adapter. You need to verify (and adjust, if necessary) that both gauges read exactly the same. It does not matter what they read, only that they agree with each other. Once they agree with each other, you can remove the "T" and connect each gauge to its own carb. By doing that, you will know that any differences you see when the gauges are connected to their own carb is due to a difference in carb sync, not gauge calibration.

That extra step is only necessary with those dial-type gauges and the stock Suzuki "ball" gauges. Virtually all of the other gauges can simply be connected to the carbs without the calibration step.

.

[biker bitch]

For pretty much the same reason that Cadillacs don't look like Toyotas.

You have a different product from a different manufacturer that happens to do the same job.

What you have will work, but you will have to take an extra step every time you hook them up.
The first thing you will need to do is to connect both gauges to the same carb at the same time by using a "T" adapter. You need to verify (and adjust, if necessary) that both gauges read exactly the same. It does not matter what they read, only that they agree with each other. Once they agree with each other, you can remove the "T" and connect each gauge to its own carb. By doing that, you will know that any differences you see when the gauges are connected to their own carb is due to a difference in carb sync, not gauge calibration.

That extra step is only necessary with those dial-type gauges and the stock Suzuki "ball" gauges. Virtually all of the other gauges can simply be connected to the carbs without the calibration step.

.

I hear you about the toyota and the cadillac but which is which, sort of like the tortouise and the hare. I mean I know some people think the more expensive, luxury one is better but I prefer fuel efficiency. Anyway you look at it, I accepted the gift without checking the price tag.

That's enough philosophy, back to mechanics.

In order to avoid an extra trip to the store (the bus and my carbs pulled apart bike is my main transportation), I came up with an alternative to the T adapter. Let me know what you think. My synch actually has four guages even though I only need two. So I'm thinking...I can hook up two and then switch them. If one carb gets a similar reading from two gauges, great. If not I can try the same with two others until I find a pair that match up. Though the T-adapter does sound easier. and I might have to go to the store to get hoses anyway...

Ah, don't you miss hearing a woman ramble on and on.

[tkent02]

You are over thinking it... Not really necessary to use the fancy equipment on a twin. Just raise the idle speed, unplug the spark plugs one at a time, check the engine speed running on the other cylinder. Do this to the other cylinder, compare numbers. Adjust the synch to get the speeds the same.
Plug the spark plugs back in, readjust the idle speed, you are done.
Maybe it will not be perfect, but it will be close enough most riders can't tell the difference.

[biker bitch]

You are over thinking it... Not really necessary to use the fancy equipment on a twin. Just raise the idle speed, unplug the spark plugs one at a time, check the engine speed running on the other cylinder. Do this to the other cylinder, compare numbers. Adjust the synch to get the speeds the same.
Plug the spark plugs back in, readjust the idle speed, you are done.
Maybe it will not be perfect, but it will be close enough most riders can't tell the difference.

when you say adjust the synch, what do you mean?

[tkent02]

Adjust the synch screw or screws so both cylinders run evenly, one isn't doing most of the work while the other one just lollygags along.

[countrycummins99]

thanks i understand it now i was over thinking it thank you for clarifying it i hate gas motors wish this thing was diesel lol

It won't matter, you can't adjust them "higher or lower".

You can only adjust them so they are balanced.

Whether they happen to be "higher or lower" is irrelevant.

The carbs have to be open a certain amount to provide enough mixture for the engine to run. One carb is pushed open by the idle speed screw. In Lena's case, that is the right carb, #2. In your case, cummins, it is also the right carb, but you have two-barrel carbs. There is a screw between the carbs that will adjust how much the left carb is opened. As you open or close the left carb, the vacuum level will drop or rise, respectively. When that vacuum level matches the level of the other carb, lock that screw into position, you are done.

For those with other four-cylinder bikes (yours is the only one with the two-barrel carbs), the process has to be repeated, as there are a total of three sync screws that need to be adjusted.

.

[Steve]

thanks i understand it now i was over thinking it thank you for clarifying it i hate gas motors wish this thing was diesel lol

You'd still have to run the rack on it and balance the Jake brake.

.