Gasket sealant

Dirt Bike Technical discussion. This is for a little more in depth discussions :-)
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60something
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Joined: Sat Mar 03, 2018 6:45 pm
Location: Midwest USA

Gasket sealant

Post by 60something » Wed Mar 07, 2018 9:15 pm

I imagine this subject has been discussed, but I haven't found a clear answer...in my KX500 engine rebuild, I am using cometic gaskets. Is it neccessary to use any kind of sealant on them? I'm in HVAC for a living, and when I rebuild a centrifugal compressor, all the gaskets are oiled before assembly. In the olden days (back in the 70s), I fancied myself a motorcycle mechanic and used Yamabond on paper gaskets. I'm sure this will be one of those topics with as many opinions as posters :D , but I really would like a definitive answer, if there is any such thing. Thanks in advance.
I don't know half of you half as well as I should like, and I like less than half of you half as well as you deserve.

2006 KDX200 qty-2
1987 KX500
1991 CB750 Nighthawk
1973 H2 750 Triple - gone but not forgotten

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Sandblaster
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Re: Gasket sealant

Post by Sandblaster » Thu Mar 08, 2018 2:14 am

You want a definitive answer? :o :shock: :lol:

http://www.cometic.com/p-35446-custom-gaskets.html

Aramid Fiber
A premium high temperature, high-density, creep-resistant material that requires no re-torquing and is fuel resistant. All Cometic fiber materials are asbestos free and require no additional sealants.

Aluminum Foamette Material (AFM)
AFM is a chemically blown, compounded nitrile synthetic rubber bonded to an aluminum core with temperature resistance of over 250°F. AFM material has an 85 percent recovery while maintaining strong torque retention. AFM does not require gasket sealers or re-tightening.

All that being said.
There are occasions where I will still use just the slightest skim of Yamabond or similar..
Occasionally I will use it on intake gaskets and base gasket.
On the 2 piece clutch cover gaskets I will occasionally use it depending on how flat they came out after all the welding, grinding, ect.
But for the most part you don't need it.
If bikes are for kids I'll never grow up.

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60something
Posts: 57
Joined: Sat Mar 03, 2018 6:45 pm
Location: Midwest USA

Re: Gasket sealant

Post by 60something » Thu Mar 08, 2018 3:43 am

:) That's definitive! Thanks Sandblaster!
I don't know half of you half as well as I should like, and I like less than half of you half as well as you deserve.

2006 KDX200 qty-2
1987 KX500
1991 CB750 Nighthawk
1973 H2 750 Triple - gone but not forgotten

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