June 25, 2009
[Click pictures for a better view]
I've been working slowly on the forks for the past few weeks. A lot of distractions lately, but things are still moving.
From an appearance point of view, I knew I'd be repainting parts, but the curiously named "Dust Excluder Sleeve Nuts" also needed some attention. The chrome was pitted, there was a deep abrasion through the plating on one of them, and there had been some kind of trauma that left one of the nuts out of round. It's a little hard to see in the pictures, but one unit was distorted enough that the suspension spring had been rubbing on it. The right picture shows a mandrel I turned to force into the out-of-round opening. A little careful work with a soft hammer convinced the errant excluder to be round again. After that, it was off to the platers.
All the painted parts got either sand blasted or chemically stripped. On the left are the two "Bottom Members" almost ready for paint. The other pictures are the Top Covers after sand blasting, priming, and a coat of paint partly rubbed out. I got a little finicky about the spot weld depressions, so I filled them.
After plating and paint. Paint is 4-5 coats of black, hand rubbed after each coat, and 3-4 coats of clear, also hand rubbed out.
The next sad story came when I got a good look at the stanchions. They were both deeply pitted where the top bearing rested for thirty years.
So here are all of the parts for the forks, ready to go together. The top and bottom bronze bearings are new, along with the seals, O rings, and the sealing washers under the restrictor bolts. Also new gaiters.
First step was to build the dust excluder assenblies. This is really just installing seals and O rings. Apparently some time during '71, there were two seal designs. One was a conventional pressed-in single-lipped seal with a sparate "wiper seal" on top of it. The other design was a pressed-in double-lipped seal with a plain washer on top. If you try to order these parts today, (and I've tried it from two places), you get the double-lipped seal from one design, and the wiper seal from the other. Rather than being overly purist, and in the spirit of belt-and-suspenders overkill, I installed both, which effectively gives a triple seal. I made a alignment mandrel to make sure the seal went in straight.
The parts that go into the new stanchions. The shuttle valve is what changes the "stiffness" of the damper from jounce to rebound. I found the new stanchions had some burring around the oil holes on the inside, which made the shuttle motion sort of "catchy". I had to abrade them down.
The restrictor apparently increasingly impedes flow of oil as the suspension nears its full travel on jounce, preventing or reducing bottoming. Texts I have are unanimous that the soft aluminum washer under the restrictor bolt be renewed to prevent leaks. You'll hae to assemble a number of socket drive extensions to be able to hold the restrictor while thghtening the bolt.
Insert the stanchions into the bottom members, not forgetting to put in the plastic damping sleeve.
Then the top bearings, the dust excluder sleeve nuts, and the wiper seals:
Add springs and gaiters, and the forks are ready to go on the bike:
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