Carb line identification

[Firewall]

Good morning,
I'm in the middle of trying to replace the O-rings for my carb intake boots. I just got the carbs off but I'm a little puzzled by 2 of the lines. I haven't seen references to them before.

Referring to the carbs from left to right (1-2-3-4)

The line on #3 and the line going to the brass fitting in the center went to the fuel petcock.

The lines coming out of the bottom of each carb appear to just be for drainage purposes, they ran to the bottom of the bike and didn't seem to connect to anything

Its the lines on #2 and #4 that don't make sense to me. They didn't appear to go to anything, is this how they should be?.

This is on a 1977 GS750, but the carbs may have been replaced sometime in its past.

Any explanation or a good diagram for these would be most appreciated

Thanks,
Matthew

[tkent02]

#2 and #4 are vents, leave them open.
The one on #3 is the vacuum line to the petcock.

[Firewall]

#2 and #4 are vents, leave them open.
The one on #3 is the vacuum line to the petcock.

Thanks, I'll just leave them be.

Another moment of confusion. The guide to doing this seems to show a ring installed on the boot. Here's how mine looks:



The ring in that picture should come out of the boot and be replaced with my new ones right? I only ask because its completely flat and seems more like a part of the boot

[Nessism]

Your boots don't take an O-ring. The first year 750 was like that, or at least some of the bikes were. You might consider replacing the boots with new, updated parts to assure they will seal properly.

[Firewall]

Your boots don't take an O-ring. The first year 750 was like that, or at least some of the bikes were. You might consider replacing the boots with new, updated parts to assure they will seal properly.

Well there goes wasted time and money....

New boots aren't in the budget right now. Any suggestions for a temporary fix?

I've seen references to them being soft rubber. These appear to be a hard plastic on the engine side and a softer rubber on the carb side. Is that how they should be?

[Firewall]

By the way, I don't know much about the history of this bike but it is entirely possible these boots aren't very old (unless the lack of an o-ring makes them old?)

[Nessism]

By the way, I don't know much about the history of this bike but it is entirely possible these boots aren't very old (unless the lack of an o-ring makes them old?)

Yea, the lack of O-ring indicates they are old. The parts fishe shows the O-ring type and doesn't even reference the other type.

The boots are supposed to have a protruding lip of some kind. If yours have this then maybe they will seal okay. If they don't have anything than maybe a gasket is in order? Not sure.

[Firewall]

Yea, the lack of O-ring indicates they are old. The parts fishe shows the O-ring type and doesn't even reference the other type.

The boots are supposed to have a protruding lip of some kind. If yours have this then maybe they will seal okay. If they don't have anything than maybe a gasket is in order? Not sure.

I assume you mean a lip of some kind on the side that faces the engine. I've only pulled one off but its about as flat as it could be.

I suppose I'll just wait until I can afford new boots

Thank you for your help Nessism and tkent02

[TeamDar]

That sure looks like an o-ring to me. That is how old burnt dry o-rings look. I have replaced o-rings like that many times. Take an ice pick and dig that out. You will find that they are hard and brittle. There will be a groove left to install new o-rings.

[Nessism]

That sure looks like an o-ring to me. That is how old burnt dry o-rings look. I have replaced o-rings like that many times. Take an ice pick and dig that out. You will find that they are hard and brittle. There will be a groove left to install new o-rings.

That's not an O-ring, it's part of the boot.

[TeamDar]

If you say so

[Firewall]

Having already decided on new boots when funds become available I figured I had nothing to loose and started picking at the ring I could see. Whether or not it started life that way, it definitely seems to be a part of the boot now

[bwringer]

I don't see any reason you couldn't make a gasket for these, as long as the boots aren't otherwise damaged or cracked.

Probably not ideal, but it should get the job until you can buy new boots.

You can get sheets of various gasket materials in any auto parts or hardware store. I don't remember the name of the gasket material you're looking for, but I'd stay away from the paper/cardboard type and the rubberized cork.

[Nessism]

If you say so

At first I was shocked to learn about the O-ring less 750 boots too. If you look at the parts fishe there is even a reference to the boots that says "B,C,EC,N,EN; GS7508:WITH 09280-32006" (09280-32006 is the O-ring). From what I gather Suzuki changed at some time mid model year 1977 and added the O-rings.

The early GS400 also doesn't have O-rings in the boots either, and the parts fishe photos support this too. Strange but true.

[Firewall]

Awesome news, by dad had helped my brother pay for some stuff earlier this week so he paid for me to order a new set of boots. Hopefully BikeBandit will get them here pretty quick