Topic: CB400F exhaust gasket diameter

[Alaxy Galaxy]

I'm trying to find suitable alternative copper crush gaskets for my CB400F, but I'm scratching my head with the diameter.

The ones sold through partzilla using the OEM part number (18291-028-000) have an outer diameter of "about 39mm." Now, I measured my exhaust ports and they have a max diameter of 37mm. Am I missing something here?

[Alaxy Galaxy]

Check out ebay, quite a few sellers list ID, OD and Thickness as well as an abbreviated cross reference of other bikes that use the same part.

Thank you.

Should the gasket be a different size than the port to take into account the fact that it will be crushed?

[Alan F.]

I've honestly never measured.

[bryanj]

But are partzilla selling Honda parts or aftermarket using the Honda number, at one you could say Honda never packaged wrong but its hapening a lot now

[Nurse Julie]

But are partzilla selling Honda parts or aftermarket using the Honda number, at one you could say Honda never packaged wrong but its hapening a lot now

OEM are still fitting just fine Bryan but yes, afrermarket ones are a couple of mm too big.

[Alaxy Galaxy]

But are partzilla selling Honda parts or aftermarket using the Honda number, at one you could say Honda never packaged wrong but its hapening a lot now

I don't think I've ordered from Partzilla, seeing as I'm in Canada. I usually go to my local Honda dealer for genuine Honda parts. I ended up ordering some 38mm OD military copper crush washers.

[Bodi]

Not sure that copper washers are ideal. The OEM gaskets are not solid metal, there are several types but all are pretty soft. Really old ones had asbestos stuff wrapped in wire and newer ones are thin copper folded over something fairly soft.