Will GS1150EF carbs work in a GS1100G?

[Guest]

Hi, Cleaned my GS1100G carbs yesterday and one of the slides rolled off my bench and split the diaphragm when it landed on the floor. I need a set of wheels to go to work tomorrow as my car is going in for a pre-booked service.

I have a set of standard 1150 carbs that I can clean up and install but if it is going to involve re-jetting to make it work then it wont happen today.

Anyone done this swap before?

[BassCliff]

Hi,

I thought the 1100 uses BS34SS and the 1150 uses BS36SS carbs. If so, I think you're out of luck.

Parts-n-More sells the slide/diaphragm assembly for a reasonable price. Have you checked there?

Carb Slide Diaphragm ($75)

#20-6053 | Suzuki GS1100G (1982-86)
Carb Slide Diaphragm Made In Japan OEM Ref#13500-49200/38310








EDIT: Oops, just noticed that you're in NZ. That means your carbs might be different and getting parts from the States will definitely be more expensive. Sorry.

Thank you for your indulgence,

BassCliff

[Colin Green]

Thanks Basscliff,

That looks like a good deal. The shipping for that shouldn't be too bad as it isn't real big.

I just went an got a little pot of liquid tape which I will apply to the top side. I will let a sample cure for the 30 minutes or so stated and try it in some petrol before I put any on the underside of the diaphragm as i don't particularly want to have to clean liquid rubber out of my carb jets.

I don't know if it will work but I recall reading that someone here (or somewhere) used a spray on liquid rubber to do the same thing with some old and very worn (thin but not holed) diaphragms to breath a bit more life into them.

My concern is that the tear is too close to the slide and that there isn't enough surface area on that side of the tear to allow for a decent key. Nothing to lose though so am off to give it a go.

[Colin Green]

First coat. You can tell I'm an artiest eh!

[Colin Green]

Doh! Second coat but look at how the test patch dies in the white container once in contact with petrol. 75% of it is floating in the petrol.

So even assuming that the uneven application wasn't going to constrict movement of the diaphragm, looks like she's a no go.

Guy in the store didn't know if it was soluble in petrol. I guess I should tell him. Another $30 down the toilet.

[Steve]

I would be rather concerned that the diaphragm is no longer flexible.

It needs to be quite flexible to roll up and down very easily as the slides open and close.

.

[rockford]

Yes

I would be rather concerned that the diaphragm is no longer flexible.

It needs to be quite flexible to roll up and down very easily as the slides open and close.

.

Absolutely, totally, 100% correct!!!

[Colin Green]

Lol! Indeed it is now stiff as cardboard.

Another dead idea even if it wasn't petrol soluble.

[GSexpress]

silicon gasket sealer works for a while. Clean it with alcahol and just put a very thin coat on both sides just around the tear.

[Colin Green]

silicon gasket sealer works for a while. Clean it with alcahol and just put a very thin coat on both sides just around the tear.

Thanks. Just tried that, waited to dry, re-assenbled and installed into bike ready to turn the gas on tomorrow morning... in the event that the test patch hasn't completely dissolved in its petrol bath overnight.
Which brings to mind the question I thought of earlier... Just how much if any petrol actually gets on the diaphragm? If it doesn't get wet it won't be a problem.

Anyone have any ideas on that one??

[Flyboy]

Hi Colin, looking at the design of the piston and diaphragm, I would say that very, very little would actually make it onto the diaphragm, if any at all.
Consider that as the fuel enters the venturi from around the needle, it is a highly atomised state already, and considering that as soon as it enters the venturi it is drawn straight towards the motor under vacuum, and if you consider the very small tolerance between the piston and the bore of the carburetor, i would be very surprised if any fuel made it up as far as the diaphragm, considering the only way it can get there is between the bore of the carb and the piston.

[GSexpress]

The flow through a carb is not smooth and linear. It pulses, particularly in a single carb per cylinder set up like our bikes. As the intake valve opens and closes the flow pulses. This means that at times the fuel air mix is actually pushed back out a little between valve openings. As there is an open passege to the top of the diaphram ( that's how the CV carb works by venting venturi vacuum to the top side of the diaphram to suck it up) Fuel vapors can reach it. Silicon sealer is made to resist gasoline so it's not a problem. But the silicone doesn't adhere well enough to survive the flexing of the diaphram over time. I't might last a week or 2, maybe a month. So get a new one and put it in when you get it.

[Colin Green]

Just got up, checked the sample (was ok other than the small amount that dissolved when I first put it in last night) turned her on prime counted to 20 then fired her up. Purred like a kitten .

Just off to drop the car in for a service then back here to suit up and ride her to work.

Thank you for all the helpful advice.

Have a nice day.