The speedo drive on my '58 99 only seems to be engaged in the rear wheel gear when I unscrew it from the speedo and gently pull it. When screwed in and engaged in the speedo it isn't engaged. could there be spacers or similar missing from the gear drive fitting that would prevent it disengaging when pushed from the other end?
Hello Mark - There is…
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Thanks - I'll have another…
Thanks - I'll have another look at the speedo end of things.
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SMITHS website
Hello Mark, The following URL is the SMITHS website with information and specifications: https://vintagebritishcables.com/ . They are the SMITHS go to place and great folks to deal with. Hope this helps. Mark
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That's a great link..
..thanks Mark. Heartily recommend downloading the document therein to everyone, "The Care of SMITHS Instruments, Troubleshooting Speedometer Cables." Great period style info and illustrations! It suggests greasing the inner cables periodically, something I can't recall doing!
(Way back when, a mate had a very knackered Mini. It must've had severely worn bores and other problems: the blowby pressurised the cylinder block & box to such an extent that it would gradually pump oil up the speedo cable, and the clockface would visibly fill with oil, to drain away when he turned off the engine. Happy days!)
On the topic of original Smiths documentation, I have attached a single page snapshot which I think was posted on here some while back. This lists the correct numbers (ie on the clock face) for 1949-61 Nortons, as well as the correct length speedo cables. If anyone has any updates to it for other years, that would be a great help too.
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Hello Mark - There is usually a brass ferrule attached to the inner cable at the instrument end. It is positioned such that the inner cable reaches the drive square in the instrument even when the ferrule reaches the stop against the cable outer. This means it cannot reach the square in the instrument drive. They often work loose and require resetting. Otherwise the inner can drop back until it hits the end stop in the speedo gearbox at the rear wheel. You may need a couple of attempts to get the position correct for your set-up. If the ferrule has worked its way up the inner it may no longer reach the drive square in the gearbox. It very much depends on the length of the inner cable relative to the outer and where the ferrule is positioned. It very often happens to the Tacho drives on racing bikes. Bit of a nuisance really....... Good luck, Howard