O-rings leaking after 1 year

[Pete in PA]

1 year ago I rebuilt my carbs and replaced the fuel tube and T o-rings with nitrile ones.  Leaking now.

Has anyone bought the $9.99 Viton o-ring kit from Harbor Freight and it had the right sizes?
The T has different sizes than the tubes.

92 750 Nighthawk

[mollusc]

I have used kits of both types (Metric sizes, of course), and I don't remember that there were any issues.  My bike has been down for a couple of years so I can't confirm that they didn't leak.

[Bob H]

Has anyone bought the $9.99 Viton o-ring kit from Harbor Freight and it had the right sizes?

No - I bought the OEM gasket set from Partzilla. (Correction - from Randakk's)
I just matched up what I was removing with the bag of loose O-rings and gaskets. Didn't measure them.

My original ones appeared to have been leaking due to being flattened out where press against the carb.
They would leak if the bike was stored for more than a month or so, and the leaking would stop after a few days when the O-ring wasn't dried out.

[Pete in PA]

I'll have to go measure the sizes.  I also have a set coming from Ebay. They have 2 sizes. Don't say Viton, but say will not break down with gas.🤷

https://www.ebay.com/itm/133402092357?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=IMTpFHWJSia&sssrc=4429486&ssuid=IwajBBFPTpq&var=&widget_ver=artemis&media=COPY

[Bob H]

Well I have some extra O-rings. You need 2 for that T-fitting? I will send you 2 O-rings.
Initially I posted that I thought they were the same size as the other fuel rail O-rings but they must be different because this is what I marked on my notes from last year.  Each kit comes with 2 of those O-rings, looks like I have 6 left over.



And when I gathered my junk it nudged my memory - I actually got the gasket sets from Randakks based off their description of how awesome their O-rings were. And it turns out their distributor is Dime City Cycles now... but the O-ring sets are marked as K&L made in Japan.

[Bob H]

Partzilla wants 54.82 for each carb gasket set, and looking at the old O-rings I kept and labeled, and left over parts I kept and labeled, the upper 2 O-rings are the outer fuel rails and the 2 O-rings at the bottom of this image are for the inner "T" fuel part (the black plastic one).

So you end up with Extra O-rings when you order 4 sets.  I will send you the inner "T" fitting O-rings from my left over parts.

I was reluctant to spend over $200 for the gaskets on top of all the other parts I was ordering, but the main reason I went with Randakk's was their write up on how superior their parts were.

the parts I received were made in Japan, who knows they may be the same parts.

[Pete in PA]

I appreciate the offer!

Do they state what they're made of?

The more research I do, the more I'm not sure if Viton is right either.

Nitrile is definitely wrong.

I DO know K&L is great quality.

I'll use the ones I already ordered at this time.  Worst case they leak in a year.🤷🙄😡

[Bob H]

I appreciate the offer!

The 2 O-rings for T-fitting are on their way to you.
Left over from my Randakk's order.

Do they state what they're made of?

I am assuming Viton per this article
https://www.randakksblog.com/viton-proof/

When the parts arrived from Randakk's I was kind of surprised they were packaged by K&L, made in Japan.
I was expecting something exclusive to Randakk's - but at any rate they are not leaking and I had 6 extra O-rings because I only needed 2 of the 8 that I received from the 4 carb set. So you should be OK with the 2 that I am mailing out to you today.

They say this at the bottom of that article:
CBX / CX500 / FT500 / DOHC Four / etc. Orings
Customers of Randakk's Cycle Shakk can rest assured that all of the orings in Randakk's Master Kits are actually made of Viton®!

I suppose they source parts that they consider good, and make their own where necessary per this comment in that article:

Plus – through proprietary molds and other tooling assets, we make many other Viton® components ourselves via our own exclusive manufacturing arrangements. The proprietary components made in Randakk's molds are not available elsewhere.

[Pete in PA]

Wow!  Thanks!!

Viton for the win!

[Pete in PA]

So I used both Dime City and Randakks vehicle search and no 91-03 750 Nighthawk listed...Weird.

[Bob H]

Looks like they don't have availability of what I bought from them last year.
I just searched also, starting here https://www.randakks.com/motorcycles/Honda
and then searching through all of their carb rebuild kits regardless of model, and it's not there anymore.

The China Ebay stuff is still available, and I actually ordered a full set for 4 carbs last year. But I just put those in storage, figured if I am going through all that work I should get the best parts I could find.

That is a lesson to start the bike up at least every few weeks (or drain the carbs).
Draining the carbs for storage caused my old O-rings to leak though, so I am glad to not be working out of state anymore. Riding is good maintenance.

[Pete in PA]

That's not good. I drained for the winter, then just filled them and mine leaked.  The O-rings were cracked like they were there for years.

[Bob H]

The O-rings were cracked like they were there for years.

Do you know if it was just the inner "T" fitting that was mentioned, or is it all of them including the outer ones?
Honestly it is a pain in the ass just to get everything apart.

After pulling the carbs with battery box and rear fender in place, vs doing it with rear plastic fender pushed down and battery box slid backwards, I am always going to do it with the stuff moved out of the way from here foreword. It is just too crowded otherwise, even with rubber lube applied to the intake boots.

[Pete in PA]

I replaced all of them last year. drained the carbs in November, then filled them a week ago. Gas everywhere.  Pulled the carbs apart and all the o-rings were hard and cracked.
Now these were nitrile from a $5 kit from Auto Zone.  Are there different qualities of nitrile? Probably.

I'd like to find a good source of long lasting o-rings.

Also looks like not draining the carbs might stop any leaks.  Might try that next winter.

[Bob H]

OK so Randakk's no longer stocks the K&L rebuild kit I purchased from them last year.
Out of Curiosity, I went to the K&L web site and they no longer list the kit 18-2430

I noticed they had links to their catalog, and I confirmed they used to list it:



Turns out they are available on Amazon (18 left) https://www.amazon.com/Supply-Economy-Carburetor-Repair-18-2430/dp/B001KO2SU0
And Dennis Kirk https://www.denniskirk.com/k-and-l/carburetor-repair-kit-18-2430.p173153.prd/173153.sku

In order to have a complete set of the fuel tube fitting O-rings, 2 kits would do it (not 4) because each kit comes with 2 rings for the T-fitting and 2 rings for the (smaller) outer fuel tube fittings of which 4 are needed.

Randakk's was well known for their focus on older Gold Wings, keeping them on the road. This is what they had to say about the carb kits they stocked:
----------------------------------------------
All of the ordinary round orings and many other components in Randakk's Master Carb Overhaul Kits® are made of genuine Viton®. In fact, every oring we've ever shipped has been made of Viton®!

There are actually many "grades" of fluorinated synthetic rubber like Viton®. Randakk's uses the same spec material that Mercedes and Toyota use in fuel system components that are subjected to the oxygenated "gasoline" marketed in North America.

Plus – through proprietary molds and other tooling assets, we make many other Viton® components ourselves via our own exclusive manufacturing arrangements. The proprietary components made in Randakk's molds are not available elsewhere.