Air Cleaner Housing O-Ring Damage found during Valve Checks

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dnktng
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Jun 5, 2011
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630
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Western Washington
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2010 NT700V, 2015 CB500X
The "Soft Buna-N" material has an equivelant hardness of a door seal. PERFECT!! Fifteen for $8.23 item 2418T181 at McMaster-Carr. If Honda doesn't come through with a part number, this should be worth trying. I promise, I will not post again today on this topic now that everyone is asleep.
 

elizilla

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There's a "soft Buna N" o-ring with an A50 hardness, could this work?

(edited to add) Never mind, I see you found it. :)

I do like McMaster-Carr. If you end up ordering let me know how quickly you get things. I frequently find something from them on my porch, the morning after ordering, even though I don't buy priority shipping. I've often wondered if they just have a warehouse here and make a point of delivering fast because of all the little auto industry firms here in SE Michigan, or if they'd be equally fast to deliver anywhere.
 
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Joined
Jul 20, 2011
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Coldwater, Mississippi
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2010 Silver NT700VA
I found one of my O rings broken when I did my first valve check. Same problem as everyone else, no part number. I just went down to my local Ace Hardware and found one that was as close a possible. It fit in the groove and was thick enough to make compress when I re-installed the air cleaner box. As the O rings are only to create a seal so air doesn't leak in, I don't think the exact fit is required.
 
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Dec 13, 2010
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86
Location
ACT, Australia
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Black 2006 NT700V
I now have two genuine replacement o-rings in my possession courtesy of the Australian National Motorcycle Service Manager for Honda and Honda Europe.

As dnktng said these o-rings are spongy/squishy and, as can be seen in one of the photos he posted, they appear to be made from o-ring cord as they have an obvious join mark.

I don't have a micrometer to measure them so I'll take them somewhere to get them measured - I'll post the info as soon as I have it.
 
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DirtFlier

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Troy, OH
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[...I just went down to my local Ace Hardware and found one that was as close a possible...I don't think the exact fit is required...]

A common sense, practical solution to this problem. And I'm sure those O-rings will work perfectly.
 
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ACT, Australia
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Update: I sent one of the squishy o-rings I received from Honda to a friend who works for a seal manufacturing company and this is his analysis of it:

Thanks for posting me the squishy O-ring. It is so squishy (what a great word!) because it is made from rubber tube and glued together. Did you see the joint ... where it's glued?

It is clearly a special thing (49.7mm ID x 3.1mm cross-section) ... designed to be over-compressed or to adapt to misalignment, in comparison to a standard O-ring. I'm afraid I can't help you with a non-OEM replacement, but I can supply you with standard nitrile (NBR) O-rings of almost the same size. Using the Japanese Industrial Standard for O-rings the closest standard size it comes to is a G50 (49.4mm ID x 3.1mm cross-section). The NBR material is good for water, mineral based oils and greases, petrol and diesel fuels.


However, knowing the exact size, I have now found a BMW o-ring of almost the same size and composition that is used in an almost identical application (to seal an intake manifold) - BMW part Number 11-61-7-504-543. Apparently this o-ring measures 50mm x 3.2mm and is made of silicon.

According to information contained in The Seal Man's O-Ring Handbook? (extract attached) the properties of silicon seals are:
  • This polymer has both excellent heat and low temperature capabilities.
  • This material should be used as a static seal, because it has poor tensile and tear strength.
  • Basic Temperature Service Range: -75?F (-60?C) to 390?F (20?C)
  • In Typical Applications O-rings Come Into Contact With: Dry Heat, Oxygen, Medical, Low Temperatures.

I've also found an aftermarket supplier of an equivalent o-ring: ECS Tuning

Still haven't received an update re a Honda part number ...
 
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dnktng
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Jun 5, 2011
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630
Location
Western Washington
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2010 NT700V, 2015 CB500X
O-ring, 50.5 x 3.5, 91358-MG9-003
Finally getting around to the valve checks again and have the air cleaner off. This o-ring is the better fitting o-ring for the bottom of the air cleaner. My spliced o-ring appears to have held up fine. I'm replacing both orings with the 91358-mg9-003 o-ring.
 
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Mar 2, 2016
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Silicon Valley
Just finished the valve check at 3,000 miles, since I don't know if the previous owner did the 600 mile check. All were within spec. Today, when reinstalling the air box, I accidentally actually read the section in the manual which stated to check the O-rings for damage. Sure enough ... one appeared to have been cut completely through, creating a gap. Maybe it was a glue joint that separated, since it has been mentioned that the O-ring is made of tubing glued end-to-end. I noted the squishy nature of the material and, although I could see the logic of such a material in the application, it doesn't seem to be a very durable material. Sort of like those grey foam loudspeaker driver surrounds that start to rot as soon as they are manufactured. I grabbed my large Storehouse assortment of rubber O-rings which can be had from Harbor Freight for maybe $10 for perhaps a couple hundred O-rings in assorted sizes. The largest size fit right into the groove in the air cleaner housing. The firmer composition didn't seem to matter when the funnel screws were tightened. Cheap, Chinese rubber O-ring assortment to the the rescue again!
 
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