Well this is electrical, or mechanical, or a combination of the two:
The odometer stopped working on my trusty K100. It worked briefly and then intermittently when I first got the bike, and now has stopped altogether.

The trip meter will reset - except for the last digit (tenths). This makes me think that the motor that drives the odometer is geared so it first drives the trip meter, and then that is geared to drive the main odometer. If this is the case... then the stuck "9" on the tenths is why nothing is advancing.

Anybody messed with this? Is this a stripped or broken gear tooth on the odometer? Maybe a bad motor driving the odometer, jammed somehow so the trip meter can't reset?

Can I safely take the gauge housing apart to get to this section without goofing up the rest of the stuff? I'd hate to go poking around inside, only to ruin the (currently working) speedo and tach gauges.

THANKS IN ADVANCE for help and advice!

Have you checked Eastern Beaver Company web site. They have a good tutorial about fixing the instrument cluster. This is very detailed and there is a lot of pictures.

Whoa! THANK YOU! THANK YOU!

I'll report back with the results!

One bit of caution which I don't think is described:

careful with bending those ribbons which are nothing more than "wire" connections between circuits.

If you bend them too much they will crack. It happen to me.. i had to chase the connections to find the brake and solder around it.

Well... I took the speedo apart yesterday, and the news was not good: the smallest of the gears that drives the odometer mechanism, the one at the end of the motor shaft, had about half of its teeth stripped off.

No fixing that: a new gear is the only solution, and noway are those sold separately.

Used speedos are still pulling in big $ on eBay. Maybe someone has an extra sitting on the shelf that ... they used other parts out it? Maybe a crashed shell where the guts are still good?

Oh, and while I had it apart, solved the mystery of why the 'first stage low fuel light' didn't work: previous owner had removed it! A good mod, I think... silly to be blinded by a yellow light when you have nearly a half-tank left. But now that I don't have an odometer, having the light would almost make sense.

I'm sure that I have read somewhere that the gears are available because the BMW cars (as well as others) have similar gears in their speedos etc.
Check with a local instrument repair shop before going the expensive way of buying a whole speedo/tacho second hand set-up.

Replacement gears are available. Have a good internet search.

Try this: http://www.odometergears.com/bmw.html

Regards,

Phil

Wow! Thanks!
Glad I was sitting down. 4 plastic gears for $85. Whoa!

I'm gonna do some more searching before I pay that kind of coin!

Okay... starting research... I just checked Palo Alto Speedometer ( Palo Alto Speedometer website )and YES they have the little tiny plastic gear.

They will fix my odometer and install this gear for a mere $125.

They will NOT sell me the gear to do it myself.

The search goes on!

Just a thought: can you check with a hobby or a toy centre. They may have something that goes with build kits ... cars, trains..etc.

Does anyone have any more upto date info on this , it seems all links here are now broken ( Eastern Bever still exists but all helpful BMW contents seems removed ).

I don't get much on a google site search here except for fitting after market alternatives.

My specific problem is I have two busted speedo units ( well the tacko side in fact ) from which I'm trying to get a working one. I need to swap a pcb and the plastic support which smashed in a crash.

Now needle fell off the crash and appears to be push fit on some splines, however, I can't pull the needle off the intact one to strip it down.

I'm being pretty cautious at this stage but it does not seem to pull off so I'm taking time out to avoid busting it.

Any tips from someone whose already been there ?

Also I have the same odometer breakage with the smallest cog having lost 2 teeth and fallen off. Any solutions to that at < $125 ?

TIA.

use a fork to lift the needle off the splines ...works well

perhaps you could use the search feature  in the portal page ...lots of posts exactly about this  through the ages

thanks Charlie.   When I said "google site search" I meant a google search "site www.k100-forum.com ....." , I think that is the same thing that the portal page does. After that, it all depends on exactly what you search for ....


Thanks for the fork tip, I was a little wary that I was doing something that would break the mechanism. At least I now know it does pull off. In view of the posts I've seen, most of them seem to be sharing tips on how to re-glue it once it's broken !

I managed to swap parts with old one and recover the white plastic support and the smashed PCB without needing to pull the needle.  I also ended up recovering the speedo mechanism off the old one which still has a working odometer. ( Actually, I have a recollection that it's just the trip counter which works but I'm not back on the road to check that yet ).

I kept the best of both and have a reasonably tidy pair of clocks, both working. I'm going to grab a second hand pair in case it all falls apart or ready for the next time there's a arse on the wrong side of the road and I need to do some unscheduled dirt tracking with the brick.

I was told one of the reasons that the gears turn into cheese is caused by the use  of non compatible grease on the gears. I was told either dry or a compatible grease.
Regards Martin.

interesting.

It seems it is always the smallest gear which goes.  I found mine rattling around in the bottom of the box. It had two teeth missing. I had it in my rolled it idly around in my fingers and it broke into four bits. It basically has lost all structural integrity. Rotten plastic.

On the face of it , all the others seems intact.