Topic: cb750 O-Ring source

[JohnG]

While working on my CB750 I have often run unexpectedly into O rings that should be replaced as they are old and rock-hard.  An example is the oil tank lines. 

Recently I was working on the oil pump and wanted to replace the ORings there before putting it back in. Same size O-ring as the oil filter bolt,  15x2.5.  I called the Honda dealer locally who had 2. He could order more. List price $4.32 each. (yes, for one O-ring!)

I poked around the web and found metric O-rings. I was hesitant about using them as they will go in the engine and be subject to alot of heat. However I found charts that listed the good and not-so-good characteristics of different materials and found "Viton" to be the material of choice for high temp applications.

Bottom line: I got 20  15x2.5 mm O-Rings from an outfit in New Jersey for about $39 including shipping - a little less than $2 per O-Ring.  The outfit is SIS and they have an on-line catalogue
at  http://www.sisweb.com/ .  The order showed up in quite good time.

What I did not look into but should have was those little O-Rings that go underneath the cam tower supports on top...

                  john - MA

[rbmgf7]

if any of you live in a larger city, look for a store called Harbor Freight. I went cruising in there one day and they had a metric nitrile O-ring kit sitting on their shelves. it has hundred of o-rings. i've been rebuiling my kawasaki and it has replaced nearly 90% of all the rubber o-rings. the best thing about it, i only payed $8 for the set.

here's the link
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=91512

[JohnG]

remember that for ORings going in the motor in high temperature locations, it is not only the size of the ORing that matters but the material...

[chung]

I typically use the ones from Honda but if you are buying ALL the O rings for the engine, then it does add up
 At 'older" prices it was almost $180 for all the gaskets, O rings and all the seals.  But i like Genuine Honda parts for some things and this is one of them

 All Honda O rigs have the size in the part description. I use a dial caliper to measure SAE sizes if i use Auto store stuff.

Some one here mentioned using HVAC O rings in problem areas.(airconditioning stuff) That was several years ago, might find it on a search?

[Dennis]

I typically use the ones from Honda but if you are buying ALL the O rings for the engine, then it does add up
 At 'older" prices it was almost $180 for all the gaskets, O rings and all the seals.  But i like Genuine Honda parts for some things and this is one of them

 All Honda O rigs have the size in the part description. I use a dial caliper to measure SAE sizes if i use Auto store stuff.

Some one here mentioned using HVAC O rings in problem areas.(airconditioning stuff) That was several years ago, might find it on a search?

"Some one here mentioned using HVAC O rings in problem areas.(airconditioning stuff) That was several years ago, might find it on a search?"

You are referring to the green rings, correct?

That might have been me ..... I got caught on a weekend and needed one desperately for one of my Yammies. It worked fine, still working at least 6 months later. I just want to add that it was used on a fuel petcock. (Now you know why I was desperate - nothing like a fuel leak.) I don't know how they will do at higher temperatures. There does not seem to be a problem with oil and gasoline.

[chung]

Could have been you Dennis. But I was thnking motor parts. Some problem area like the head to cyl case that always leaked after a couple years.
The HVAC material holding up longer than the original rubber is the way I recall it?.

[Dennis]

......... But I was thnking motor parts. Some problem area like the head to cyl case that always leaked after a couple years.
The HVAC material holding up longer than the original rubber is the way I recall it?.

 

Well, I know that I never used them in an engine and I don't recall that post.
I don't even know what material they are molded from. I soaked the one that I used on the Yammie petcock in gasoline for 1/2 hour before I installed it just to have some idea how it would take exposure to fuel.
Without knowing what the material is, I have no idea how they would react to the temperatures in the cylinder head.

Does anyone  remember that post?

[chung]

That one goes waaaaaay back to the old site.

[yesplease]

Not sure if this is any help, but I recently picked up a pack of ~50 rubber O-rings 3/4-1" down to 1/4-3/8" (ID/OD for each) for a buck at one of the dollar outfits. Maybe there are metric sets out there someplace?