[guss,guss]

Hello Gearheads.
 i guess i've had that carb off so many times the rubber seal under the cap has come loose. And its getting hung up on the spring. I can see where it had four little dabs of adhesive holding it in place, from the factory. I was going to glue it back with either clear RTV silicone or permatex ultra black.
 i would like to know which of those would be a better choice. Whatever Mikuni used looks clear .   
 Thanks.

[Blltrdr]

Which carb are you using? The stock Mikarb has only an o-ring. Should not have any sealant/adhesive from factory.

[guss,guss]

 this is a mikuni vm32, not the mikcarb.

[Blltrdr]

this is a mikuni vm32, not the mikcarb.

That helps. Whatever adhesive that will hold with the use of gasoline. Looks like you either fix by re-adhering it or you purchase a new cap. That Permatex Permashield looks like there only product that might work.

[Vince]

     Gasgacinch. It works great on carb float bowl and anything around gas, and it does not stick so bad you tear things taking them apart. Lightly coat one side. Let air dry for a few minutes, then press on while still tacky.

[guss,guss]

I found gasgacinch on Amazon and a permatex high tack sealer popped up. they both say they resist gas...  I'm going to get some gasgacinch to keep around for stuff like this.
 Thanks guys.

[cafeman]

I believe it's just a flat rubber ring. Cut a section of old inner tube and make a new one, or just use a piece of cardboard from the backer of a notebook. Or an autoparts store has rolls of thick gasket material and cut a ring. Don't get hung up on the material needing to be exactly the same, all youre doing is sealing the cap to the body to prevent air being drawn through. The Mikuni tm uses a paper type gasket. Don't go using goopy stuff!

[Arizoni]

Almost none of the silicone RTV's resist gasoline.

Permatex 85420 Permashield Fuel Resistant Gasket Dressing & Sealant or Hylomar Universal Blue Sealant are fuel resistant.

[Ice]

 Gaskacinch is gas resistant and fantastic if you want to take it apart later and without tearing the gasket. Use Seal-All is gas resistant also gear oil resistant. Use it if you want the thing stuck on for eternity.

[Hondo]

There is a product called "Seal All". It can be found at most hardware stores and believe it or not Dollar General. It will seal gasoline. I have seen my dad spread it on cardboard and stick it to a leaking fuel tank and stop the leak. I always keep a tube in my shop. Hell even found it on Amazon! https://www.amazon.com/Seal-All-380011-Seal-All%C2%AE-oz-Adhesive/dp/B0000AXYZG