Categories: all aviation Building a Biplane bicycle gadgets misc motorcycle theater
Tonight was fork-night for the old Honda. I tried to make yesterday fork-night, but the forks weren't cooperating, and I didn't have time or energy enough to figure out what was going on.
What I did do yesterday was to drain one of the fork legs of its oil. Well, I say oil, but what I mean is "oil" in big quotes. What actually came out of the fork leg was a quarter cup of water, followed by what appeared to be the original fork oil: dark green sludge that dripped lazily out of the drain hole in the fork slider. I didn't make any further progress than that.
Tonight, I drained the other fork leg. Instead of water followed by oil, what I got was a horrifying, thick white sludge that appears to be emulsified oil and water. The resulting mixture that's currently sitting in my oil drain pan does not look like anything I'd expected to get out of any part of any motorcycle, ever. It does look like something I'd expect to find along the Cowgate in Edinburgh, or outside frat row at any major university in the US. That is to say, something with disturbingly organic origins.
In any case, that decidedly distasteful topic aside, I set about trying to solve the problem of how to actually remove the forks. Each fork leg is held in place by two clamps, which are collectively called the triple tree. Triple because you've got the two fork legs, and the central pivot tube. The lower triple clamp had pretty obvious bolts, which I loosened. The upper triple clamp, unlike any other bike I've worked on, didn't have any clamps I could see, just a big bolt in the top end of the leg, which served as both the attachement into the top clamp as well as the plug holding in the "oil."
So, normally, getting a fork leg out is a simple operation: undo one clamp bolt, remove the top bolt, and pull. In my case? Naturally not that simple. I couldn't actually get either leg to budge until I'd entirely removed the top clamp from the bike, and spent several minutes' quality time with a big hammer. Finally, I dropped out the left fork leg, which was covered in rust.
Next came the curiously difficult task of removing the accordion-like fork boot. This is the piece of rubber that covers the sliding surface, nominally to keep it from getting dinged up by flying rocks or bugs or whatver. In the case of my bike, what it had actually done was provide an excellent container to keep several inches of water pressed against the very corrodable fork leg. Extrapolate that against 35 years of life in the great, rainy Northwest, and you can imagine what kind of shape the fork slider was in. Let's start by saying it was Not Good, and conclude by saying that one of the areas of pitting was so deep that a good-size grain of sand could have ridden from outside the fork leg to inside the fork leg without touching the oil seal.
The other fork leg, once I finally got it out (which involved considerably more time with my big hammer -- I'm going to get a blacksmith's arm if I'm not careful) was in much better shape, with only one comparatively tiny area of pitting.
I called Tim, the wonderful repository of all 160 parts, and asked if he had a spare set of fork legs I could buy from him. He said he might, but he'd have to figure out if another project required them, so I'll be calling him back on that front. However, he did suggest an interesting idea: rather than scrapping the forks (which was my only thought so far), why not try filling the pits with JB Weld? It's not as if the surface of the fork tubes actually has to be that hard, it just has to provide a smooth surface for the oil seal to ride on. It's an intriguing idea, and one I'll have to explore further.
Of course, the screws holding the slider to the tube are both completely frozen, so the question may be moot. If I can't get the sliders off, then I can't replace the seals, and there's no point trying to fix up the tubes. In that case, I might as well just refill the forks with oil and plan to spend a lot of time cleaning up oil gushed up past the ratty seals. Unfortunately, that will never pass the technical inspection at the race, so that idea's pretty much a non-starter.
So now, I've got the forks sitting on the workbench, with penetrating oil soaking into the frozen screws. I'll have to hit up Sears for a variety of replacement screwdrivers, as the ones I have are all starting to look a bit rounded. There's a lot to be said for that no-questions replacement policy...
But hey, progress is progress, even if it results in disgusting sludge and the feeling that I'm taking two steps back for every step forward.
Posted at 23:28 permanent link category: /motorcycle
Categories: all aviation Building a Biplane bicycle gadgets misc motorcycle theater