On spooge and silicone

Nope. This post isn't about kinky sex with enhanced supermodels. Nor is
it about increasing your diameter....

Anyway, last weekend, I noticed that the leftmost carb of my Nighthawk 550
was leaking from the seam between the carb itself and the float bowl.
Monday night, I went to Schlep Boys and bought a tube of silicone sealant
that was supposed to be gasoline-resistant, and sealed the float bowl
seams of all four carbs with a *very thin* smear of sealant. Well, today,
I took the bike for a 100-mile trip. On the way back, I noticed that the
bike had very poor acceleration and was running rough.

After I got home, I stuck a wet rag on each exhaust pipe in turn. The
three left pipes sizzled as expected. The rightmost pipe hissed weakly.
I checked for spark, and all four cylinders were sparking strongly. Ok, I
thought, so the problem must be the carbs. I whipped off the carb rack
and found that some silicone had gotten into the float bowls and was
turned into a gelatinous mess by the gas. A small blob of jelly was
blocking the main jet of the right carb completely. I cleaned out the
bottoms of all the jets with a pin, and I think that I've removed most of
the spooge that was causing the problem. The jelly in the float bowls
themselves just wiped off with a rag. Now, I just need to find the
correct O-rings to seal the bowls to get rid of the initial leakage
problem. I'll either order the Honda parts, or I'll order rings of the
right thickness and diameter from McMaster-Carr if the Honda parts turn
out to be unreasonably dear.

Moral of the story: silicone sealant + gasoline = bad things

Oh, and does anyone know of a solvent that will dissolve any lingering
remnants of silly-cone? Removing and reinstalling the carbs is an
annoying task, and I hope not to have to repeat it.

Thanks,
Andrew

 

I'm not sure you're blaming the right thing.

My understanding is that the RTV silicon out of a tube cures in the presence
of water, like with the humidity in the air. I think Krazy Glue works this
way also.

Once I went on a web quest to find a solvent which would dissolve cured RTV
silicon. Some of the solvents, if I remember this right, was stuff that's
just not practical to work with at home, like ether. And they don't dissolve
it, just soften it up.

I've seen that jelly krap in carbs, when I've seen it it's come from letting
old gas evaporate from the bowls.

RTV silicon and gasoline are probably perfectly compatable, once it's cured.
Don't know about in between.

D.

 

Nope, the bowls were clean last week when I tore down the carb bank. The
nasty spooge was mainly around the float-bowl/carb interface, making me
pretty damn sure that the silicone was in fact the problem. Hopefully, I
good soaking in carb cleaner will get rid of any lingering pieces of
silicone, and after I find appropriate o-rinds, I can go back to riding

-Andrew

 

I don't know of any silicone product that is actually fuel proof, regardless
of salemen's claims. I soak siliconed parts in gas to remove it. The ethanol
or alcohol present in modern gas prevents using the old standbys like
permatex too. The only fuel proof sealant than I know of, that is also
alcohol proof is Hylomar.

 

Well, dang it, you got my hopes all up!

 

JB Weld is fuel proof

Well, it is for at least 4 years as that's how long I've had a slab of
it patching up the gas tank of my cage..

 

sounds as though you didn't let the silicone cure properly first before
refitting and allowing the cards to fill or you applied to much silicone

 

Methylene chloride swells and softens it, causing it to lose adhesion. It's
not a solvent and you'll still have to remove the RTV mechanically.

 

Permatex Motoseal is supposed to be the best for gasoline resistance.
I used an anaerobic gasket maker a couple of years ago on my Honda
nighthawk carb float bowls because they were leaking and I would have
had to buy a complete rebuild kit (4)just to get the gaskets. 18 k
later, still no leaks. Lee

 

Thiokol polysulphide adhesive sealant. They were trying to brew up a better
synthetic rubber when they found it also made a hell of a rocket fuel. The
solvents will attack some plastics, but it is a great metal to metal bond.