Wing tips #9

Tips and Recommendations from Guru Mike Nixon

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mikenixon
Early 'Wing Guru
Early 'Wing Guru
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Wing tips #9

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Post by mikenixon »

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Blue silicone worms, on the oil pump pickup of a SOHC Honda 750. A sad sight, but at least the screen caught some of the crap. This scene is just as I found it. Nasty!

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 car's replacement head gaskets. You could glue a bridge together with it! 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. I like this on carb diaphragms. 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. Thus worms are always created,

Proper sealers intended for use on engines, including the one Honda recommends (but doesn't always use themselves, apparently) 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 between cases and other places where sealer is legitimate,

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The assumption that dual-output coils fail only both outputs, never just one, is false. As far as how a dual-output ignition coil works, it's true, since the two plugs fire in series, the failure of one of the outputs either at the plug or elsewhere on the coil's secondary side, should result in neither output working. However, although a failure usually happens that way, it doesn't always, and the industry has known this for 50 years at least. When one side of a dual outout coil fails, the electrical strain built up in the secondary winding wants badly to return to its source, the battery, and will try hard to find a path. What can and occasionally does happen is the secondary winding will arc internally, inside the coil assembly, back to the primary, thus allowing one output to work while the other does not.

Two interesting things. First, this possibility of internal monkey business is so strong that it is why you never want to remove the plug wires from your plugs and crank the engine, without first defeating the ignition system. You'll note that Honda had kill switches way back in the 60s (and still do) do that very necessary defeating for you while still allowing the starter to work. The other brands' kill switches used to defeat the starter as well as the ignition (though they caught up to Honda during the early 1980s). Not so handy. Second, this tendancy for the coil to arc internally is why BMW boxer ignition coils had special "lightning rods" built into them. The only ones to do so to my knowledge, and for a very special reason. Ask if interested.

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I am alarmed at how many times I have seen on the Internet suggestions to use thread locker on fork bottom bolts. Never! Shudder!

Yes, I am aware that at least some official Honda manuals include putting thread locker on those Allen-headed damper rod bolts, but I find this terribly amusing, in the same way watching someone step on a cat's tail would be! First, Honda never, ever put thread locker on any of their 70s and 80s street bike forks at the factory. Why that is found in some of their manuals is really curious. We career techs used to moan about why couldn't Suzuki, who did always put thread locker, be more like Honda, whose forks could be disassembled without first using a gas torch on the bottom bolts, as you had to do with Suzukis.

Second, and this is the main point, you have to understand what thread locker does and how you have to work with it. It wasn't that we were lazy. It's a matter of putting your wrench on the bolt not knowing it is Loctited and promptly buggering the heck out of that delicate Allen head. You think this is of little concern? You wouldn't if you had to spend a couple hours or even a whole day trying to get a trashed damper rod bolt out! If a mechanic knew that a fellow mechanic had, however innocently, set him up this way, he'd probably throw a wrench at him! In fact I had to drill out a fork bolt just two weeks ago. Turned a fork seal job into a whole day affair.
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