Sealing header pipe gasket with Copper RTV?

[rugbywarrior89]

Hey all, I have a very small leak on my left side header since I got the bike. I bought a non copper set of gaskets from Mikes that didn't work then I tried copper rings that came with the xs400 gasket set on ebay. I have also changed the header pipes. Still have a small leak. I'm starting to think the engine surface might have a scratch or imperfection of some kind preventing a good seal. I was thinking about putting a bit of copper RTV in there with the copper gaskets to fill in any voids and hopefully seal the leak. Its rated for 700 degrees and I was under the impression that head got over 1000 but the permatex sight suggests it for motorcycle headers. I also saw online where people have used it on their cars with good success. anybody care to share their opinion on this matter? Thanks

 

[xschris]

Are you running the stock exhaust hooked to where it should be. If your running some other setup my guess is you head pipes are not lining up where the should be. My 2-1 on my 80 did that when I first put it on till I found the sweet spot and no leaks.

 

[rugbywarrior89]

No I bought a used factory exhaust. I'm not sure how they could be out of alignment. They don't really move very much once the crosspipe is connected and they are bolted to the frame (not tightened). The previous exhaust was stock headers with shorty mufflers.

 

[xschris]

I would also make sure there is not more than one gasket already in there.

 

[rugbywarrior89]

I took two gaskets out (one on ech side) when I replaced them but I guess that not to say the PO didn't double gasket them. I will double check that. Could this issue cause the 4000 rpm high rev problem?

 

[xschris]

Most likely a small leak will not. That sounds like a carb issue.

 

[rugbywarrior89]

Thats what I thought as well, thats why I never brought it up until now but I'm still having that issue. I figured it was worth fixing just to check it off the list of possibilities. I think it's just a matter of tuning now and not actually any mechanical failures. I've cleaned those carbs 3 times now and replaced the butterfly seals and intake boots. I can't find an air leak anymore so I guess its probably just the mix screws, float adjustment, and balancing from here.

 

[rugbywarrior89]

At any rate would copper RTV work in this situation? I'd still like to know.

 

[xschris]

I have never used it.

 

[KFunk740]

Ultra Copper works fine at the header pipe junction. I've been missing one entire header stud for years and the ultra copper keeps it solid (threads are mangled and it won't be fixed easily).
You shouldn't use to fix a gaping hole, that won't work. But for sealing a gap between two metal pieces that are loosely squeezed together without a gasket, sure.

 

[rugbywarrior89]

Welcome to the forum KFunk. That makes me feel much better to know someone else has used it at the headers. Thanks for the help.