Can you dismantle a speedo

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Is there any way to take a speedo apart without screwing it up?
Thanks
 

Lineslinger

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I once dismantled and reassembled an Angenieux 25mm - 250mm zoom lens, with good results.
I would attempt that again before a taking on a Smiths speedo.
I gave the speedo from my 60' Healey a try and ended up sending all the parts off in a box to the local Pro's from Dover. Quite a few specialized tools needed.
 

baz

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Is there any way to take a speedo apart without screwing it up?
Thanks
If you are talking about a magnetic Smith's then yes you can carefully prize the bezel off
You need to work very slowly and carefully
You can buy a kit that includes the glass the seal and bezel if you've damaged any of these parts
You will never get the factory rolled finish on the underside of the bezel but if it's for a commando it won't be seen when mounted in the pod
While the clock is apart drill a hole in the case where the adjustment screw is and you can strap a satnav on and calibrate the Speedo perfectly
 

Craig

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VintageBritishCables .... they rebuild smiths , excellent work ... Alberta Canada ....
 

NPeteN

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I did mine, it's easy.
The gear was gummed up and inoperable, I freed it and it works like new.
Ordered new bezel, rubbers and glass from Vintage British Cables (thanks Craig) as well as proper tach and speedo cable. Recommended.
 

fiatfan

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I have a speedo from a 1970 Commando in really good condition, apart from the small fact that it doesn´t work.... Here in Sweden there´s only one company that can fix these old clocks, I asked them and they said that there´s a damping oil in there somewhere that get thick and hard over time. So you have to take it totally apart. They wanted almost 200£ to fix it...... Not interested in that. But from some of the replies above it seems you can do it yourself, I have the set with new parts for it. Maybe give it a go?
 

fiatfan

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I did mine, it's easy.
The gear was gummed up and inoperable, I freed it and it works like new.
Ordered new bezel, rubbers and glass from Vintage British Cables (thanks Craig) as well as proper tach and speedo cable. Recommended.
Can you tell how you freed it, did you take the whole thing apart? I have the same problem it´s stuck.
 
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.... Here in Sweden there´s only one company that can fix these old clocks, I asked them and they said that there´s a damping oil in there somewhere that get thick and hard over time. So you have to take it totally apart. They wanted almost 200£ to fix it...... Not interested in that. But from some of the replies above it seems you can do it yourself, I have the set with new parts for it. Maybe give it a go?
Who are they? Need a renovation for a 99.8% original bike.
Only one I know of on the right side of the pond is https://www.classic-speedometers.com/
Not to offend anyone, right side is as seen on a map. ;)
 

NPeteN

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Can you tell how you freed it, did you take the whole thing apart? I have the same problem it´s stuck.
Nope, just opened up the clock, removed the main mechanism and worked the gear slowly back and forth through the cable drive until it loosened up, probably used a little lube. Once you have the guts out it's plain to see.
 
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You will never get the factory rolled finish on the underside of the bezel
If you have a Lathe you can make a fixture to hold the speedo/tacho with the bezel and rubber compressed and then you can roll the bottom of the bezel over the lip of the main case.

 
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fiatfan

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If you have a Lathe you can make a fixture to hold the speedo/tacho with the bezel and rubber compressed and then you can roll the bottom of the bezel over the lip of the main case.

It's basically called metal spinning or spin forming...look it up!
You don't use a tool post, but a handheld tool like you are wood turning.
A skilled person would have done six speedo bezels on the time it took to make this video.
 
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my 2-cents -- before starting anything, get a copy of this book...

IMG-2705.jpg
 

baz

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It's basically called metal spinning or spin forming...look it up!
You don't use a tool post, but a handheld tool like you are wood turning.
A skilled person would have done six speedo bezels on the time it took to make this video.
I have a hunch that kommando knows all about metal spinning
 

Bodger

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Always wondered if you could make a crimper for the bezel out of a rotating PVC pipe cutter tool by replacing the cutting discs with small brass pulleys to create a crimping radius.
 

baz

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If you have a Lathe you can make a fixture to hold the speedo/tacho with the bezel and rubber compressed and then you can roll the bottom of the bezel over the lip of the main case.

That's brilliant
I had wondered how it was done keeping the rubber seal under compression
 

DogT

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I've got both mine apart at the moment, but I'm working on some way to roll that bezel back on without a lathe. I haven't come up with a good solution yet, but I'm thinking about it. All I had to do was replace the rubber gaskets around the 3 screws and I got new bezels and glass while I was at it. EuroJamb sells a whole kit with bezel, glass and SS screws and rubbers. I had worked on one a long time ago and I just crimped the bezel on with some channel locks.
 
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