Over the last week I've noticed my speedo needle randomly waving about like a flag in a gentle breeze. I could be doing 80kph and the needle falls down to 40 and back up to 60 and falls again. It's never higher than my actual speed.

The odo is working perfectly. I've checked a couple of lengthy trips against Google maps and its spot on so I doubt there's anything wrong with the pick-up on the rear wheel or any of the wiring from there to the instruments. It's got to be in the speedo mechanism itself.

While I've had the instrument pod part to change globes and dry it out on the odd occasion, I've never delved into the mechanics of the speedo.

The instruments, in all other respects have been working faultlessly up till now.
Any suggestions as to what might be the problem before I go pulling it apart?

Hey!

The same issue occurred with my speedo.
Cleaning the connections helped.

Three places you could clean.

1.) the sensor at the rear drive

2.) the cable connection at the right side, where the plate with the frame number is.
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3.) the speedo it self needs some cleaning, many screws but easy to take apart, could be moisture, put it on the heating for an hour.
You don't have to take everything apart, just open and use carful some DeoxIT Contact Cleaner.


Cheers

KH: as Espresso says, don't assume it's a mechanical fault. LFB pulls the same stunt on occasions; disconnecting and reconnecting the PCBs fixes it for another year or so i.e. it sounds like light corrosion.

The odo is working fine so its getting correct signals from the sensor. It can't be anything external to the pod.
I'll give the PCB contacts a spray with cleaner. I have done quite a few hours of wet weather riding over the last few weeks, some of it torrential and the front is naked. Not seen any condensation inside tho... as is usual after a ride in the rain.
Cheers

If you tap the face of the speedo while it's waving around, does it come back to normal?
I suspect corrosion either in the main plug into the unit or one of the three plugs under the speedo it's self.

On the same topic, where do I get odometer gears?

Rockman wrote:On the same topic, where do I get odometer gears?

http://www.speedometergears.com/bmw-mercedes-odometer-gears

http://www.repairsonly.com.au/index.html

try these Phil

If it is the small main drive gear..you can get it with a few other gears from Jaycar..total cost about $8 as opposed to at least $25 for that one gear alone.

Kaptain, I'd expect the needle to be more sensitive to signal than the odo, but that in itself would lead me to check the connections for corrosion.
Intermittent signal loss and intermittent signal decay or waning would show up at the needle mostly and would lead me to check for continuity.

mine did the same nigel

try cleaning up the speedo sensor cable connector  at the connection at right hand side cover

mine starts playing up periodically after a wet weather ride ....but a few weeks - months later

deoxit helps

smithy wrote:If you tap the face of the speedo while it's waving around, does it come back to normal?
I suspect corrosion either in the main plug into the unit or one of the three plugs under the speedo it's self.

Thanks for the pic smithy. That'll make it easier to find the coections.Tapping makes no difference. 

Keith/Charlie. I understand what you're saying there. Will investigate further. Just haven't had time to scratch myself since I got back from up North last w/e. And now can't find my DeoxIT. Must be still in my storage shed.

Cheers

Oh, just take out a mortgage and buy another bottle!

Yes, its grossly overpriced in my opinion.

I just wounder if CLR (Calcium Lime Rust) would do the same. It cleans up tarnished metal ok. Then flush it out and squirt with WD40...??

Espresso, Keith, charlie... Spot on. Looks like it was the connector r/h rear of tank. Gave it a clean with brake cleaner (isopropyl alcohol), jiggled it in and out a few times and it looks like all is good in K-world again. It was a bit dirty and it seems a bit loose so I'll need to do some maintenance on that connector sooner than later.

Keith, looks like you may be right. It seems the needle may be more sensitive to random signal fluctuations than the odo.

Cheers

RicK G wrote:

Rockman wrote:On the same topic, where do I get odometer gears?

http://www.speedometergears.com/bmw-mercedes-odometer-gears

http://www.repairsonly.com.au/index.html

try these Phil

The odometer & trip meter stopped working on the 100/2. Took it to Repairs Only and it was fixed in 2 days. 4 damaged gears replaced. Gears are from Odometergears.

Richard.

Just in time guys! My Speedo has been acting up and finally quit working. It would work up to 40 mph and lock up.It would not indicate more than 40 but worked fine under. Well,it stopped altogether now. I now know what to look for before pulling it. Thanks forum!

Maybe Speedometer disc is warped...

Mike Bergenstein wrote:Just in time guys! My Speedo has been acting up and finally quit working. It would work up to 40 mph and lock up.It would not indicate more than 40 but worked fine under. Well,it stopped altogether now. I now know what to look for before pulling it. Thanks forum!

Have a look at the magnetic pickup in the final drive. Take it out and check if there are any metal particles stuck to it.

And if you remove the speed sensor, if you put a soldering gun to its proximity, the speedo needle shoud start to move.
BUT.....
Sixt1 just released the latest version of Karamba.
You just have to manufacture a piece of wire with a 3.5" jack and plug your computer on the bike. You will see right away if you have a problem with the speedo/connections or if the problem is the sensor.