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Sunday, 5 July 2015

More time in the garage

Due to pressure of work etc I haven't done an awful lot on my bikes recently, just an hour or two here and there until today when I managed about half a day. Further to the last post I started on the front end of the SZR. I'm using an ABBA stand, which holds the bike by the swing arm pivot. Unfortunately, the SZR is so 'nose heavy' that even with the front wheel out it still wants to fall forwards, so I've had to use a strap onto the roof frame to hold it up. (Note to self – never buy a bike without a centre stand again!)
The wheel came out OK, and I soaked the disc bolts with penetrating oil for about a week. Even so, they wouldn't some out even using heat and an impact driver, so I had to cut a slot in them with an angle grinder and use a chisel and a very large hammer. Once the disc was off I cleaned up the wheel, smoothed the surface and repainted it. The disc was cleaned up, the centre repainted, and refitted using new bolts. I wouldn't say I'm paranoid, but I used threadlock AND new Schnorr washers, 'just in case'.
The left fork leg had been leaking from its seal, so out it came. Bolts had been sprayed with penetrating oil and came out very easily. With the fork on the bench it was now having to work out how to take it apart as this is the first time I've worked on 'upside down forks'. The manual mentions a number of special tools, but I've not been able to find them online, however I did find a couple of articles by people who had done the job themselves.
First tool needed was a very slim 14mm spanner to hold a locknut that is only accessible through the coils of the spring. So it was out with the angle grinder and I thinned a spanner down until it fitted.

The manual shows a special tool that fits down the forkleg outside of the damping mechanism to remove the cartridge. Numerous bikes use something similar and I found plenty available online, (Motion Pro makes a range of them). These are usually about £50, far more than I would want to spend on I job I am only likely to do once, and nobody listed a tool for my Italian made Paioli forks anyway.
One online report mentioned making a tool (basically a long tube with a 'castle' type end on it), so it was rummage round the garage for something suitable. A couple of years ago, a neighbour asked me if I could take an old table of hers to the dump. I dumped the glass top, but as the frame was made of steel, I cut it up and kept it, 'in case it came in handy'. Well, guess what was just the right size – one of the legs from the table! Five minutes work with a hacksaw and it looked like this:

I just guessed at the dimensions, but when I tried it I could feel it engaging with the nut. I had thought that it would be a bit weak, but the nut came off when I turned it. You can see how near I got to the right dimensions here:

Once that was out, I removed the circlip holding the seal in, held the fork bottom in the vice, and pulled the forks apart. A gave it a few pulls (which give a very satifying 'clonk') and I could see the fork seal starting to come out. A few more and the forks were apart.

The job was a lot easier than I had thought it would be, so don't be afraid of taking USD forks apart.
I had a good look at the forks and there is no noticable wear or damage to the sliding surface. I'll give everything a clean and replace the seal. You are supposed to use another special tool to drive the seal into place (it's recessed quite far into the fork), but I'll make something out of PVC drain pipe. I'll have to remove the bushes (the grey and bronze 'rings' round the tube) to fit the seal, but as they are split that's easy enough. You are supposed to use another special tool to compress them to reassemble the fork, but I'll make one out of PVC drain pipe with a Jubilee (worm drive) clip round it.

Forks seals only cost £6.20 from M&P, and I'll have to buy some oil. So far so good!

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