Speedometer question

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Speedometer question

Postby MalcW » Wed Mar 25, 2020 2:33 pm

Hi all. Are any of you familiar with the innards of a chronometric speedo? Mine works fine as far as speed, odometer and trip go, but resetting the trip is difficult. It's as though something isn't meshing properly; you get there in the end, but it's a long process. Weirdly, if you twist the reset the other way it advances the numbers easily.

Cheers,

Malc

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Re: Speedometer question

Postby clive » Wed Mar 25, 2020 3:09 pm

I imagine yours is the bottom trip. Usually the cause is that the casing holding the trip return shaft has come loose. Unfortunately the screw which holds it in place is hidden behind the shaft. To get at it you will need to remove the needle and face so that the trip reset will come out. I suggest loctite before you do the screw up again. Getting the needle off is easy if you undo the screws from the face and then place a knife blade underneath the face near the needle and twist it against the brass frame. The needle should pop off without damage. Getting the bezel off can be fun. When I used to repair them for club members I put them in a poly bag in the freezer for a couple of days and then took them out mounted them in a bracket in a vice and using good leather gloves turned them off. Its brass on a steel case and why heat did not work but cold did I have no idea. Its possible but less likely the problem is the bar which pushes down the operating arm so allowing the numbers to be turned backwards. This bar is on the trip return shaft.

If it is a side trip life is easier the screw holding it in place can be accessed without taking the face off.



Something to do :roll:
clive
if it ain't broke don't fix

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Re: Speedometer question

Postby MalcW » Wed Mar 25, 2020 3:34 pm

Hi Clive

Thank you for the information; I'll give it a go. As you suspected, the reset is on the bottom, so I'll do as you suggest and see what I can see. I have removed the bezel on this one once before, using a bit of protective leather and a car oil filter wrench - the type that looks like a giant pair of pliers, so hopefully it will move this time.

As you say, it's something to do.

Malc

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Re: Speedometer question

Postby clive » Wed Mar 25, 2020 3:47 pm

come back to me via PM if the problem is not a loose casing, or I might have to tell myself off for advertising on the forum! :rofl:
clive
if it ain't broke don't fix

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Re: Speedometer question

Postby Group Leader » Thu Mar 26, 2020 8:21 pm

No please reply on the forum as the one outstanding thing with mine is the trip is a nightmare to reset.

You won't be advertising Clive just providing valuable information to the members :D

Now, if you need a Top Hat bearing I know someone who might have one ...... :rofl:

Alan
1953 AJS 16MS, 1939 BSA 250 and a 1/3 scale Sopwith Triplane but that's another story ..... :lol:

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Re: Speedometer question

Postby clive » Sun Mar 29, 2020 5:11 pm

Alan I will happily provide any additional information on the forum, but won't offer to have a look if Mark cannot fix it on the forum as I would then fall foul of myself......
clive
if it ain't broke don't fix

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