O-ring needed for TK26 carbs

Gone through the 1982 GPZ-550 carburetors and they are clean as a whistle now but the O-rings on the pilot jet plug have disintegrated.
The plugs, original orange in color, are good, but I am not having any luck finding replacement O-rings.  I think the part number is 92055-1337.
The dimensions need to be about 3.5 mm inner diameter and 4,6 to 4.7 outer diameter. 

The originals were, I believe, a bit tapered like a cork in a bottle.  Not sure if this specification really matters.
Also, a possibly silly question as I am not very knowledgeable on carbs but is this O-ring exposed to gasoline so needs to be fuel rated?  I think so. 

I have done some searches but anything I find says out of stock and I am guessing they have been for a while.
Thank you for any help.

 

Any pneumatic or hydraulic service center or hardware store sales o-rings in the size you need.

I have tried 3 sets so far.  The inner diameter of 3.5 mm seems doable, but the 4.6 to 4.7 overall diameter seems to be the challenge.
Don't they need to be fuel resistant as well?

What is the size of the passage in the carb?  

BTW, O-rings are sized by ID and thickness.

As for material, Buna N (nitrial) or viton will work.

wrote:

What is the size of the passage in the carb?  

BTW, O-rings are sized by ID and thickness.

 

The size where the plug needs to go in is a bit loose without an O-ring and measures 4.8mm using calipers. 
The outer diameter of the plug is 4.7.  O-rings with an outer diameter of 5.2 to 5.3 are a no go.  So maybe 4.9 to 5.0 is a better size to shoot for.

My understanding of the dimensions provided on web sites are the outer diameter plus the cross section of the thickness of the rubber.
So, I would need 3.5 ID with a thickness of .7 times 2 to get to 4.9mm overall.  Is this correct?

wrote:

wrote:

What is the size of the passage in the carb?  

BTW, O-rings are sized by ID and thickness.


 

The size where the plug needs to go in is a bit loose without an O-ring and measures 4.8mm using calipers. 
The outer diameter of the plug is 4.7.  O-rings with an outer diameter of 5.2 to 5.3 are a no go.  So maybe 4.9 to 5.0 is a better size to shoot for.

My understanding of the dimensions provided on web sites are the outer diameter plus the cross section of the thickness of the rubber.
So, I would need 3.5 ID with a thickness of .7 times 2 to get to 4.9mm overall.  Is this correct?

ID + thickness is the industrial standard when it comes to sizing O-rings.

I've got some 3.5 x .9mm O-rings.  Those might work.  Use some slicone grease before install.




 

I've got some 3.5 x .9mm O-rings.  Those might work.  Use some silicone grease before install.

So, is my math correct?  The OD diameter of these would be 3.5 + .9 + .9 = 5.3mm. 
We have a few this size and even with silicone they will not go in evenly.

Do they need to be rated for fuel/gasoline?
 

wrote:

I've got some 3.5 x .9mm O-rings.  Those might work.  Use some silicone grease before install.

So, is my math correct?  The OD diameter of these would be 3.5 + .9 + .9 = 5.3mm. 
We have a few this size and even with silicone they will not go in evenly.

Do they need to be rated for fuel/gasoline?

Of course they need to be rated for gasoline.  As I said previously, you need Buna N or viton.

The only other O-rings I'm aware of that may work are .8 x 3.2.

www.theoringstore.com/store/index.php?ma...60&products_id=43927

Screenshot from ebay of the O-ring in question.

This is not a super skinny O-ring.  It's very similar to the O-rings I've got here.

 

Yes, I did find those but not sure about the part number and they look a little fat around the cross-section.
It seems Kawasaki used the same part number for things then added some more numbers or letters for different O-rings.
I am getting the impression the Gpz550 is a tough find these days.
Thank you for looking for me.
 

Some auto parts stores sell individual o-rings out of a kit. If you find one of the correct ID but the OD is too large, maybe go with a smaller ID & make it fit. You could use silicone spray lubricant to install or heat it in hot hot water beforehand.  It's just a static plug o-ring, so it only needs to seal & a perfect fit probably isn't necessary.

The O-ring for the Keihin CV34 pilot plug are quite large, and get smashed down significantly during install.  The first time I rebuilt a set of those carbs, I thought the seal was a cylindrical sleeve, instead of an O-ring, because the O-ring formed that shape.  My guess is that in this application it's similar.  

And realize, if the carb hole is 4.8mm, you want the "as installed" O-ring to be about 5.2, since the O-ring must crush on install to affect a seal.