Smith's Chronometric speedos

[Don Vosper]

I see that there a number of people repairing these and sellling reconditioned speedos but does anyone sell spares for these?
Or is it a case of canniballising old ones?
Cheers
Don

[rogerwilko]

I repair my own by cannibalism. No idea where the professionals get their spares. probably a secret society. There are some parts like the 4 leafed cam spring which i wish i could buy a number of. Tell us if you get into the society!

[R]

Some of the repairers have had batches of spares made, in the past at least - ask around them and see who will supply.

[Don Vosper]

Thanks for the replies.
Did manage to repair mine after all with salvaged spares. I have one spare non working complete unit.
Broken spindle on balance wheel, if that's its proper name, but the one I put in was lighter.
I'm probably going to have to buy a reconned unit eventually as the bike is a Sunbeam S7 and it has a unique speedo with built in right- angled drive. The one I have is a straight one with a Landrover rt angle drive and I'm not sure how long it's going to last before something else goes wrong that I can't repair.
I see that even scrap speedos seem top be fetching a fair price.
Could be worth ringing around a few repairers.
Been looking on line for an exploded diagram without success so far.
Regards
Don

[Goldy]

      http://www.speedograph-richfield.com/                                                     
 These people do repairs and calibration and seem to have all the parts. All the best Goldy

[chaterlea25]

Hi Don
Classic Motorcycle magazine April 1992 has a good article on Chrono speedos
There was another magaxzine article recently, Ian Bartram gave a good description of the workings
Your balance wheel can be correctad bty adding clip on weights which were used to calibtate the speedos
HTH
John

[rogerwilko]

Here you go!  http://www.hells-confetti.com/Technical%20data/Jaeger%20Instruments/Jaeger%20Chronometric%20Overhaul.pdf

[Don Vosper]

Many thanks for the link to the repairer and the excellent article.
Have yet to try the bike since my repair. Waiting for summer to return!
Cheers
Don

[twolitre]

My chronometric speedo went haywire yesterday! Still clocking miles, but the needle has gone insane! Flirting to wildly different speeds (even 110 mph which my Triumph 5T is certainly not capable of). Occasionally it goes back to normal.
I was delighted to see the link in the above post. Hoping to learn how they work. But the link does not work on my PC.
I wondered whether it might be a simple lubrication problem and if so what kind of lubricant to try.
Jim.

[Don Vosper]

The link to the article worked fine for me. It did take a while to download though as it is a 4meg pdf file.
Seems too big to post here  as one file.
Says to use sewing machine oil after cleaning with petrol.
Don
Incidentally, just taken the Sunbeam round the block and the speedo now works but tells me I'm doing 40 when it's nearer a real speed of 50.

[twolitre]

Thanks Don!
I went back to the link and waited. The loading thingamywotsit stopped turning ages before the site came up. But it did eventually.
Jim.

[rogerwilko]

Your haywire speedo has the symptoms of a broken or bent cam spring. Exactly what i've run out of! If anyone finds a source, i'll have a dozen.

[twolitre]

Thanks everone for the links and tips.
I had non-working spare with a stuck needle. Having (more or less) sussed out how it works from the downloads. I decided I had nothing to lose by "having a go".
As I removed the innards small brass disc fell out. I could not find where it came from, so I cleaned and lubricated the works, re-assembled and tested. HEY PRESTO! It works. That probably saved about £80 from sending it away. The "foreign body" must have lodged somewhere and jammed it.
 I spoke to Jonathon Jones, the Author of the Heels Teeth download (who, by a remarkable coincidence is a friend of one of my friends). He could not identify the part, but suggested it might be part of a previous bulbholder. He was right!
All sorted and I saved a goodly sum. Very welcome after just having spent £500 on the engine re-sleeving, boring and new pistons (see post Barrel full of laughs - not).
Jim.