Author Topic: Speedo Disassemble, Inspect, Service, Reassemble, Hope  (Read 18942 times)

Online RichardL

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Hello All,

I bet this satisfies LJ's thirst for a new topic and discussion.

I think there might be interest in the Smiths Chonometric cleaning, service and repair I am underataking. I have done a fairly extensive web search and have found almost no photos (I think I found a total of 1) of the inside of a chronometric speedometer. If I am correct, with the addition of my photos, our forum will become a major source of photos for others who are looking.

Removing the bezel was the first challenge. One site said to put on a leather glove and twist off the bezel by hand. If no-go, apply thin oil. I let Liquid Wrench sit overnight and still had no luck by hand. Thus, you see my approach using two strap-wrenches, which did work.

The speedo was in much better condition than I hoped. The lubricant was sticky. I washed it out with ether starter fluid after wrapping the odometer and trip wheels in plastic food warp to avoid getting too much solvent action on the numbers, which are said to be quite sensitive to any solvent. In retrospect, I probabaly should have removed the clockworks from the frame to wash it out, but no harm was done. By the way, the speedometer truly is a clockworks, as it is designed to update speed readout every 3/4ths of a second. Recommended lubricants ranged from instrument oil to motor oil. I chose Marvel Mystery Oil  as being something in-between and which I believe to be a high-quality thin motor lubricant; this I applied with a baby's medicine syringe.

After lubrication (and quickly to avoid oil overspray from acting like a solvent), I cleaned the the odometer and trip wheels with cotton-tipped swabs and soapy water; no solvents allowed.

The one thing that was broken was the tripmeter reset shaft. Reset shafts for magnetic replicas are available, but I could not find one for this old clock, and I didn't want to wait just to find out that I can't get one. (If someone knows where I could find one, please let me know). I fumbled around my tool box and came up with an awl that was just 0.025mm larger in diameter than the 3mm original shaft, so I have fashioned a new shaft from that, as seen in the photos. The little toothed wheel and shoulder behind it are both from the original part. removed by drilling, and now swaged onto the new shaft. The tapered arm (not custom made) seen extending out from the trip shaft lifts the pawl during the rewind process.

There will be more photos and talk as I move forward, so, for now, that's it. Some of the photos are pre-cleanup and some are after. If you can't tell which is which and need to know, let me know. Also, I'm not being very disciminating with the photos, so they will be in multiple posts and in no particular order.

Richard
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Online RichardL

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Re: Seedo Disassemble, Inspect, Service, Reassemble, Hope
« Reply #1 on: 02.11. 2008 18:16 »
Here are more Smiths Chronometric photos.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Offline fido

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Re: Seedo Disassemble, Inspect, Service, Reassemble, Hope
« Reply #2 on: 02.11. 2008 19:05 »
Interesting stuff. I tried to get the bezel off my speedo but gave up in the end and sent it to a specialist. I actually broke a strap wrench but it was probably an inferior quality tool. I then tried a length of leather belt wrapped round the bezel and used one of those oil filter removing wrenches that you use with a socket handle, the sort with pivoting arms. That was just distorting the speedo case so I decided I was doing more harm than good.

Online RichardL

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Re: Speedo Disassemble, Inspect, Service, Reassemble, Hope
« Reply #3 on: 02.11. 2008 19:10 »
If the strap wrenches had not workd, my next approach was going to be to rout out or turn a hardwood doughnut with the bezel profile on the inside, split that in half, then grab it with a strap wrench or other circumferencial tool, like your belt idea.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Offline LJ.

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Re: Seedo Disassemble, Inspect, Service, Reassemble, Hope
« Reply #4 on: 02.11. 2008 21:30 »
Brave man Richard!

The speedo is a place where I have been in and come away in tears, not for me I'm afraid much too delicate. But you think your speedo bezel was difficult to get off, you should try a Military issue that has an anti tamper locking device rivet on the underside, this has to be carefully ground off before even attempting to remove bezel. I think in a lot of cases it is paint that had crept into the threads and dried which makes removal difficult. Good luck with the restoration and thanks for an interesting read.
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
1961 BSA A10  650cc Golden Flash-Blue
1961 BSA A10  650cc Golden Flash-Red

Online RichardL

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Re: Speedo Disassemble, Inspect, Service, Reassemble, Hope
« Reply #5 on: 02.11. 2008 21:57 »
LJ,

As I mentioned under another topic, I have my father-in-law, a skilled clock entusiast, as a backup if I got in too deep.

Richard
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Online RichardL

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Re: Speedo Disassemble, Inspect, Service, Reassemble, Hope
« Reply #6 on: 02.11. 2008 21:59 »
...and, yes, I did scrape around the housing/bezel junction to remove as much paint as possible.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Offline Cider1

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Re: Speedo Disassemble, Inspect, Service, Reassemble, Hope
« Reply #7 on: 03.11. 2008 15:44 »
Hi
This is very interesting as I'm about to start on my Speedo. 
Does anyone know where replacement or restored dials can be obtained?  I got one made of plastic from the bike show at Stafford.  It looked ok at the show but when compared to the original it's very poor quality so I'd like to find something better.

Cheers
Frank *smile*

Online RichardL

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Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Offline Cider1

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Re: Seedo Disassemble, Inspect, Service, Reassemble, Hope
« Reply #9 on: 03.11. 2008 18:44 »
Hi Richard
Thanks for the very quick reply.
The dials on the Austrian site appear to be the same as the one I've got.  They have the wrong type face, ie sans serif.  I think I may have to have mine refinished professionally then it will be correct.

Frank

G/F DAVE

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Re: Speedo Disassemble, Inspect, Service, Reassemble, Hope
« Reply #10 on: 03.11. 2008 20:57 »
RE;Smiths chronometric speedos these are quite a simple thing to repair (if you can obtain the parts) seems like the speedo repairers do not like to give out info of source of parts for diy repair. Basically most chronos need a good clean thats all unless they have damaged mile/trip drum numbers you can easily source new dials in brass or aluminium .The hard to obtain parts are the parts that wear ie; the sandwich plates for mechanism & springs.I have repaired several chronos  I normally give the mechanism to my mate who is a aircraft mechanic to have ultrasonically cleaned also I have used a good quality switch cleaner never use wd40 etc .I have replaced the mileage strips on the drums now this is a fiddly job but with a steady hand and a hands free magnifying glass it is possible.As for stuck bezels most bezels are past their best simple answer is to use a junior hacksaw & cut thru threaded portion once thru open up threaded part then remove dont cut deep or you,ll damage threads.Mind you I have made mistakes but have learned with time how to repair,you cant risk taking chances now at current prices for these speedos and if your not confident best left to someone in the know .Good luck if you do!!!! *eek* G/F DAVE

Online RichardL

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Re: Speedo Disassemble, Inspect, Service, Reassemble, Hope
« Reply #11 on: 03.11. 2008 21:55 »
Dave,

Too soon to know if I've done a right cleaning. Thanks for the advice regarding ultrasound. That would be a logical next approach if I have a jerking needle (no double-entendre intended).

Richard 
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Online Brian

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Re: Seedo Disassemble, Inspect, Service, Reassemble, Hope
« Reply #12 on: 03.11. 2008 22:12 »
About 35 years ago I had a friend who was an instrument fitter in the airforce and I remember watching him work on some kind of instrument and he was using a pressure pack of some stuff to clean it. I think is was called Freon, but I'm not sure, it was a long time ago. I remember asking him about the stuff because it was amazing, just squirt it on and all the grease and grime just dissapeared.

Has anyone else heard of this or has my memory failed yet again ?

Offline Cider1

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Re: Speedo Disassemble, Inspect, Service, Reassemble, Hope
« Reply #13 on: 04.11. 2008 16:10 »
Hi G/F Dave
Can you tell me where brass or aluminium dials can be obtained please?

Frank  *smile*

Richard

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Re: Seedo Disassemble, Inspect, Service, Reassemble, Hope
« Reply #14 on: 04.11. 2008 17:12 »
I do not know if Dave Woods will supply parts but he seems a reasonable chap I gave him my S/R speedo and rev counter and he repaired both and at a reasonable price.
The speedo on my Plunger is looking very sorry the bezel has had a screwdriver and hammer on it at some time but once fitted the ruber grommet in the cowl that it fits to hides it. the white paint on the dial looks as if it has been almost wiped off the word Smith can only just be read and the mileage numbers are very discoloured but at least you can tell what speed you are going.
Might get that overhauled sometime in the near future but I will not be going near it
Richard