AJS & Matchless Owners Club

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

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

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

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!

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

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

Alan

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......

OK, update on the speedo trip reset problem; it was exactly as Clive said. The casing on the side is, as Clive said, held in place with a single screw, and it also locates on a small lug. The screw is at the top, so when it's loose and you pull on the reset, it rocks the top of the casing away from the trip mileometer and the gear doesn't engage properly. It has now been done up tightly once more, along with a spot of Loctite, so hopefully that's that.

Now, does anyone know where I can get a chronometer needle from? Mine has never looked too pretty since it got caught on the top RH dial fixing screw not long after I got the bike, resulting in a bent needle. I straightened it as best I could, but it doesn't look great, and this would be a good time to change it.

Thanks,

Malc