Identifying seal 81 750

[Crankthatback]

Good afternoon.

I am currently cleaning, replacing seals and gaskets on my 81 750 carburetors.

They are very clean though a bit of work is being done here and there. (bowls were ran out then drained before parked)
The bike has been sitting for around 10 years and so my gaskets and seals are to dry to be reused.

The seal I am trying to replace are located between the bowl gasket and the main carb body.

I have looked at a few part diagrams but not able to identify this seal.

Any help will be appreciated!

[Big T]

Pilot jet plug
Need it to idle

[Nessism]

Short cuts, are LONG cuts. Follow the tutorial, and do EVERYTHING called out, or you will (likely) have to redo it.

https://gsarchive.bwringer.com/mtsac/~cliff/storage/gs/Mikuni_BS-CV_Carburetor_Rebuild_Tutorial.pdf

https://www.thegsresources.com/_forum/forum/consumer-information/gs-parts-and-services/1703182-mikuni-bs-cv-and-vm-o-ring-kits

https://www.ebay.com/itm/175906655700

[dgates1]

May be referring to that flat rubber ring that goes under the float bowl gasket...?

[Crankthatback]

Pilot jet plug
Need it to idle

I have a new set of plugs.
What is needed is the seal that the arrow is pointing too.
the gasket sits directly over it.
I think 20 years ago when I last rebuilt them I had the same question.
thank you for the response though and I am glad you are still here!

[Crankthatback]

May be referring to that flat rubber ring that goes under the float bowl gasket...?

That would be the one. : )

[KiwiAlfa156]

I've never seen a seal in that position. There is a metal blanking plug which appears to be related to the machining process during manufacture. The float bowl gasket seals this area (which the fuel pick up/air bleed for the choke circuit). I think a PO may have tried to 'improve' sealing... The nitrile plug visible in the pic blocks off the pilot jet which is fed through the main jet. Without them the bike will idle, and run fine up until about 1/4 throttle after which it will run super rich and fall on its face, as the unplugged pilot jet access hole effectively becomes the (massively oversized) main jet. Don't ask me how I know this.

[KiwiAlfa156]

Nothing on the parts diagram either.

[Nessism]

Some carbs have those seals, and others don't. I've never seen them offered for sale before.

[Crankthatback]

All 4 have them and I vaguely remember asking this question many years back the first time I took them apart.
My memory is not so good. ; )
I cannot think of a reason I would have put them there otherwise.

Now the carbs have been apart a few times from my original rebuild, but the seals were not replaced after the first rebuild.
It has been many years!

I half think I was told to use the same seal that something else on the carburetors used.

I had one of Roberts kits that I had bought or possibly given to me from Ken over in Maryland. The gentleman that raced sidecars.

He upgraded his carbs instead of using the originals and that seal was not in the set.
At least that is what I think?

I may try ordering the #57 seal in the diagram and see if that is it if knowone reading this has a answer.

To tell the truth It likley is not nessary as it looks more like a flow restriction more then anything else.

The bike always ran so well though and I would like to ensure it continues to do so.

THANK YOU!