® Sealers

At least the oil pickup screen caught it. Yes, but... This is just as I found the stuff. Not staged. Blue silicone worms.

And this is the sort of nonsense that creates the worms. If it has a gasket, it dorsn't need a sealer, and silicone would be the last choice!

This is a legitimate use and location for a sealer. Hondabond 4 is being used, spread thin, and on crankcase joints where it is indicated because no gasket is applied.

There are many kinds of sealers used around engines. BMW even had one (Dirko) that was nearly epoxy-like, and actually came in the package with their cars' replacement head gaskets. And then there's Rolls Royce specified Hylomar, at the other end of the soft/hard spectrum in its never-hardening, forever tacky, chewing gum-like consistency. Different products for different uses, right? Naturally.

That's decision number one: the right product. But, you ask, don't Honda and the other Japanese manufacturers use silicone sealer at the factory? Yes, unfortunately, it appears they do, despite their specifying non-silicone sealers in their literature. Countless times I have uncovered the presence of silicone sealer on new bikes during warranty jobs.

But there is a real problem with silicone sealer, and that is it has no surface tension. The bit that squeezes to the edge of the joint can't stay there. It has to fall into the oil supply, and that little bit will be there no matter how sparingly you use the stuff, for another issue with silicone sealer is its lack of body: it is impossible to avoid squeezing it to an almost nonexistent film.

Proper sealers intended for use on engines, including the one Honda recommends (but doesn't seem to always use themselves) have excellent stay-thick characteristics, and the squeezed portions stay attached because the material, unlike silicone, is non-hardening. It stays tacky, in other words. Hondabond #4, made by Threebond and actually the same as their #1104 product, is the real deal. I won't use anything else where sealers are called for.

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