SOHC.co.uk Forums > CB350/400
Yet another clock resto' thread
exvalvesetdabbler:
I am in the process of restoring a couple of clocks and been documenting the process as I go in the hope that someone else finds it useful. Kind of open source bike restoration. I will keep this thread updated as things progress.
The first task was to peel off the crimped rings without marking them or ending up with a screwdriver embedded in the palm of my hand. After seeing what other folk had done a large hose clip was going to be included somewhere. After a few test fits, I wasn't happy with the mechanism of the worm drive digging in to the band and marking it, and plastic sleeve inside just left some areas gripped less than others and it could easily slip off when applying pressure.
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To solve this, I machine up a collar out of some 10mm sheet plastic and made cutouts to accommodate the hose clamp mechanism and split the collar to allow it to tighten evenly over the band. It is also stepped to stop the clock being pushed through.
Also needed some way to keep the clock centered in the jig to avoid scuffing the new paintwork during re-assembly. That's the 3 screws and bushes.
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Next was the pry tool. I had to sacrifice my 'paint stirrer' screwdriver by re grinding the tip so the flat blade was angled and rounded on the back side to roll against the clock base.
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Regards
Dave
exvalvesetdabbler:
Ring expanded and open.
I did about 4 laps to get to this point, just lifting up the crimp a little on each pass.
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Its important at this stage that the ring is sufficiently open to allow the base to lift out. You could pry it out at this point , but to avoid damage to the restored base and cover its easer at this point to get the ring open to allow the base to lift out cleanly.
The next step is to clean up the base ready for plating using electrolysis in washing soda solution. I used about 2 egg cups of soda in the container size below and a current of about 250 mA. You can use steel or aluminum as the anode (+ve) with the negative connection to the base.
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And after about 12-16 hours this is what you end up with. This was the worst one that was heavily crusted with rust and some pitting is visible. The advantage of this method is that the metal and zinc plate is untouched so they can be left sitting around for a while once they have been cleaned up.
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Regards
Dave.
Johnny4428:
Nice work on the clock there Dave. I had a go on my 550K3 clocks but although it was just a cosmetic job I decided it was a job for a clock restorer so the internals could be checked as well.
exvalvesetdabbler:
Weather wasn't up to much midweek so I got on with a bit of polishing indoors.
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First I took out any noticeable scratches with some part worn 400 grit wet'n' dry and then followed that up with 1200 grit and then on to 2500 grit. Then I took the polishing machine outside and gave them a final buff up. There are a few pits left where stones have hit but once fitted to the bike they'll be hard to spot. Polishing machine is nothing fancy, just the main motor from an old twin tub washing machine with the shaft threaded half inch and the mop held on with big washers and nuts.
Regards
Dave
exvalvesetdabbler:
No stainless JIS screws in the junk box - no problem.
I mastered this method when rebuilding carbs a long time ago when stainless JIS screws were hard if not possible to come by.
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The holder consists of a piece of scrap brass that is threaded for the screw to be machined. The shoulder on the piece is the guide for the diameter. To shorten the screw, it is screwed in from the other end. The protruding piece of thread can be cut back and left chamfered and tidy. The screw in aluminum piece stops the screw backing off during machining. I find this last bit easier than running the headstock in reverse and having to keep moving the tool post.
If these were going to be visible after assembly I would radius the head a little more and give them a light polish as well.
Regards
Dave.
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