GS750 running way to rich no matter what I adjust

[xenoz]

I've got a 77 GS750

I rebuilt the carbs, and no matter what I adjust the bike still runs very rich on 3 cylinders.

I've adjust the needle clips, the floats, all the screws and nothing.

This is the first time I have worked on a bike.

So under the floats (if you have the carbs upside down) there are holes.

Well on the #3 carb (the one with the hose running to the petcock) that hole has a brass ball stuck in it. I don't know if it is suppose to be there or not, or whether it has anything to do with my problem.

But like I said I can lean out the needle or lower the floats and it has no effect, I'm still fouling plugs and turning them black.

It's becoming very frustrating.

 

[hampshirehog]

What have you got on there / done? Are you running standard pipes / airfilter, what main jets, what pilot jets, what needles, what float height?

And that nipple on #3 shouldn't have a ball in there - that is where your vacuum pipe sits to open your fuel tap.

 

[Seana23]

Hi babes.
Also... What type ov spark plug have you got in... B8ES/BR8ES?
Maybe try B7ES or BR7ES... They run cooler than 8's...
But yes, ive seen those little brass ball bearings and always wondered what they did...
Are your carbs CV's or slides....
Have you oiled the air filter recently?
Sounds like too much fuel and not enough air getting through...

Get back to us with many more details and even pictures...
Us lumpy-jumpered spanner monkeys like puctures

Xxx

 

[7981GS]

B7's are a hotter plug BTW.

Eric

 

[tatu]

Hi babes.
Also... What type ov spark plug have you got in... B8ES/BR8ES?
Maybe try B7ES or BR7ES... They run cooler than 8's...
But yes, ive seen those little brass ball bearings and always wondered what they did...

Those brass balls are important to block off unwanted holes left from drilling the fuel/airways as they can only be drilled in straight lines as they join up.

 

[MisterCinders]

Yes. Post your settings and mods, so we can figure out what to suggest.

 

[Seana23]

B7's are a hotter plug BTW.

Eric

yes, yes..... i meant it will take hotter conditions... i.e. "its a cooler plug"

XXX

 

[Seana23]

Those brass balls are important to block off unwanted holes left from drilling the fuel/airways as they can only be drilled in straight lines as they join up.

Ahhh, thx. that figures. nice one
XXX

 

[Homie]

What's the condition of your air filter? A dirty or clogged air filter will result in those kinds of symptoms. Try temporarily removing the air filter and see what she does.

 

[Guest]

Check you choke[ enrichener] and make sure that it is closing all the way

 

[xenoz]

I can't post any pictures at the moment but I'll get some up.

Everything is stock, the rebuild kit for the carbs were #102 main #15 pilot jets

BUT HERES SOMETHING FUNNY

its not all cylinders that are running rich, only the 3 & 4 cylinders.

The boots to the airbox are not airtight at the airbox should I seal that?

When I removed the aircleaner ALL the cylinders started running real rich.


I'm running the needles at one clip lean right now.

I run B8es plugs and my carbs are makuni slides

 

[hampshirehog]

You have the wrong mains in there. 102s don't exist and 102.5s aren't standard in a GS750. You shoul probably have 100s in there but check the engine number.

The clips on the needles should be in the mid position.

 

[xenoz]

Well, I will definitely pay attention the next time I'm buying something on ebay.

Thanks for the quick response.


What jet sizes would you recommend for pods?

If I'm going to have to get jets again anyway I might aswell grab some pods too.

 

[hampshirehog]

If you're struggling with attempting a standard set up I would advise against trying to set your carbs up for pods.

 

[bubby]

You have the wrong mains in there. 102s don't exist and 102.5s aren't standard in a GS750. You shoul probably have 100s in there but check the engine number.

The clips on the needles should be in the mid position.

sry if i may have missunderstood you

102s do exist they are what where in the vm26ss i just purchased
that came off a 78 gs 750 and i know this sounds like a dumb question and may have nothing to do with your problem but are the carbs synced?

 

[7981GS]

This should shed some light on the subject...

Eric

 

[bubby]

this is awesome and very helpful :clap:

 

[allojohn]

You mention carb rebuild kits, these are known to be of poor quality. Likely there is nothing wrong with the original jets, they just need cleaning along with the the carb bodies (24 hrs in Berrymans) and a new set of o-rings.

Again, check the engine # to make sure you have the right jets, the '77 had two different main jets depending.

+1 on getting your machine running properly before jetting up and installing pods. You could have a right old mess on your hands if you rush things.

EDIT: Just read Eric's post, yep you've got the wrong jets.

 

[BassCliff]

Hi,

Everything is stock, the rebuild kit for the carbs were #102 main #15 pilot jets

BUT HERES SOMETHING FUNNY

its not all cylinders that are running rich, only the 3 & 4 cylinders.

Agreed. "Carb kits" are known to have inferior quality parts. You are much better off cleaning the jets, needles, etc, and re-using the stock parts. If you must replace a part use OEM parts. All you should need is an O-ring kit from http://cycleorings.com and a gallon of carb dip.

The boots to the airbox are not airtight at the airbox should I seal that?

The entire air intake system needs to be air tight so that it draws in air only from the intended orifices. Any extra air will wreck havoc with the air/fuel ratio.

Airbox Sealing
(by Mr. Roostabunny)
[SIZE=-1](CLICK HERE to download as PDF)

[/SIZE]

Air Intake Repair: (PDF file)
Airbox removal, intake boots and O-ring replacement

Also see:

Suzuki GS Series Carb Specs

Do you have the stock Mikuni jets installed? Do you think you might have Dynojet parts? Can you tell the difference? The Mikuni part has a logo that looks something like a square within a square. They Dynojet part has only the number.

This is a picture of stock stuff. The DJ needle has a much sharper taper.

Thank you for your indulgence,

BassCliff


​

 

[hampshirehog]

sry if i may have missunderstood you

102s do exist they are what where in the vm26ss i just purchased
that came off a 78 gs 750 and i know this sounds like a dumb question and may have nothing to do with your problem but are the carbs synced?

No, you're right. I should have been clearer. Mikuni 102 jets don't exist. And a GS750 in standard fettle wears Mikuni carbs - and they probably have 102.5 mains (some of them don't - depends on the engine number).