Carb Manifold Insulator Sealant

Norman White recommends “a thin layer of liquid sealant to both sides of the insulators that fit between the manifold and the cylinder head”. What sealant is recommended?

I've never used any so I recommend none

Some use a paper gasket on each side.

I do make sure the surfaces are flat and not scratched.

Light smear of high heat silicone gasket material?

Petrol degrades silicone. I’d go with Wellseal, but then always say that !

light spray of copper coat has worked for me

Hylomar is my go-to sealant for fuel gaskets...

I also have used Hylomar for years on the insulating spacer for many years.Plus it helps holding them during installation.
Mike

I using CURIL T2

I use this stuff on fuel line fittings, float bowl gaskets, manifold insulators/ gaskets and the O-rings on carb flanges. I found it on aviation supply websites.

I have never used any sealant on my manifold insulator gaskets in 49 years and only once have I ever had to replace them when one started to leak which was about 10 years ago, if the surface is clean they shouldn't leak, in fact I use no sealant on any fuel gaskets at all, but depends on how many miles I do a year and when my Norton was an everyday rider till 2013 I do a major carb rebuild every 3 or 4 years with new replacement carb kits, jets needle, gaskets and O rings and manifold gasket if the old ones look bad, but as I have said have only had one ever leak.
Do I have a freak Norton, no I just do maintenance when I think it's time to do so but since the 2013 my Norton is semi retired since buying a New Thruxton, the Norton isn't getting the miles up when it was my everyday rider and now no longer working it's now my fun take out bike and the 2016 Thruxton is my long distant traveler, but the Norton still gets ridden regularly just not as much as it use too, and being retired not riding every day.
When my manifold gasket did start to leak, but the Norton was still running well I thought I had a blown head gasket, but it was where the fuel leaving a stain just above the head gasket, the dried up fuel looked like an oil leak at first.

I've used Permatex Grey gasket maker/sealer on the insulators to good effect. Fuel resistance not so critical as it will not be sitting in pools of fuel...only vapour passing by. Also used the Locktite 518 flange sealer....that stuff is fuel resistant.

I use Permatex Motoseal when I need a sealant..

This is one of those topics where… if you ask 10 people… you’ll get 11 answers…!

..but which one is right?

Onder said:

..but which one is right?

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the one that will stand up to the temps

Onder said:

..but which one is right?

Click to expand...

At least 12 of ‘em…

YING said:

I also have used Hylomar for years on the insulating spacer for many years.Plus it helps holding them during installation.
Mike

Click to expand...

Do you use Hylomar Red or Hylomar Blue on the manifold insulating spacer?

Red on the port side. Green on the starboard.

Onder said:

..but which one is right?

Click to expand...

The eleventh one!

Most surfaces DON"T need sealant at all. Often it is used to "fix" a problem rather than fixing the problem. Components can have warped surfaces due to over tightening and the standard gaskets/o-rings won't seal so sealant is added instead of truing the mating surfaces.