Speedo fine, odometer quit?

[Crazcnuk]

Ok, this is a new one for me, and according to my searches, for the site.

My speedometer works fine, but the odometer section no longer counts the miles. Of course, the trip meter also doesn't work.

Pretty hard to keep an eye on the gas mileage w/o the odometer.

Anyone had experience fixing one of these?

[scalded dog]

It happened to my '79 standard, had 77,000 showing when it happened, I hated to give it up, but couldn't figure out how to fix it, I figured with that many miles, the gears just wore out, replaced it with an odomeer reading 44,000. Later 'Dog

[Ivan]

The drive wire spins a magnet and there is a cup that surrounds the magnet and that part drives the needle. Off the wire there is a worm gear that drives the odometer section. It is not unheard of for old speedos to wear out enough that the gears no longer mesh. If you pull your speedo head, and take the reed switch out, you will see the gearing I am speaking about.

[Poprock]

On my 80 SG, when I reset the trip meter, the plunger stayed in, permanently disengaging the drive gears for the odo and trip meters. It's still stuck in. I haven't tried pulling the speedo apart. I'm running a Cat-Eye electronic speedo for a bicycle. It has odo function, trip function, average speed, clock time, and a counter for pedal revolutions too. It registers up to 185 mph. $30. Still on the original battery after 4 years.

[kjohnson]

It is very likely that what Ivan said has happened : the gears have just worn out. I have repaired my XJ's speedo by salvaging parts from a good speedo, but I don't trust it's longevity. I will be replacing the XJ's gauges with something from here as soon as I can. fyi, if you go that way, get the s4 pickup.

[Crazcnuk]

This one has 70,594kms on it, oh and nearly 30 years!

It's not a big deal, except that it makes it hard to keep track of fuel mileage!

[3Phase]

This one has 70,594kms on it, oh and nearly 30 years!

It's not a big deal, except that it makes it hard to keep track of fuel mileage!

Is it a Special or Standard speedometer?

Anyway, if gears wear out the speedometer will still work but the odometer and trip meter won't. Here are some pics of the metal worm drives and plastic gears on my Standard speedometer.

The main worm gear at the speedometer head entrance lost lubrication and wore out. I had to swap in another worm gear when I rebuilt it.




The plastic gears can break, lose teeth or just pop out of place.




Regards,

Scott

[Crazcnuk]

It's an 80SG Special. I would have thought it would give some warning, like slipping a few miles here and there, but it just stopped dead.

[DiverRay]

It's a gear. It works, or it does not. Special Ed's bike has the same problem, so it IS old age catching up to some of the parts that do NOT get the grease they need.