Archive of BMW Motorrad Club Cape (2006 - 2019)

The speedometer on my 1150GS suddenly stopped indicating speed.
No warning signs or noises at all. Just stopped working.
After a some effort and using previous experience, I managed to get it working again.
I will describe what I did, it may save many riders quite a bit of money.

I loosened the cable from the drive unit at the front wheel and tried to spin the cable (slow electric drill, ANTI-clockwise)
The complete cable started twisting and the inside would not rotate at all.

I then removed the cable from the speedometer instrument (you have to take off the screen and instrument cover below the screen).

Testing the cable on it's own proved that the cable seemed fine.

Trying to rotate the input to the speedometer, I realised the instrument input was locked solid.

I planned to open the instrument and to see inside what could cause the problem.
I then realised that the glass face of the instrument was crimped along the circumference and I would have to pry it open all round the edge.
Obviously that would cause damage.

As a plan B I removed the drive cable from the back of  instrument and squirted bit of Q20 oil into the input connector of the speedometer. With a small screwdriver I managed to slightly rotate the input shaft, creating hope but not success.
Then I tried Carburettor cleaner ---- suddenly more success.
I mounted the instrument in the workbench and using the electric drill at low speed, (NB rotate anti-clockwise) I continuously squirted carb cleaner into the input.

A thick pitchblack goo dripped out for a while, and then the rotation gradually became easier. NB: Ensure that the input shaft point slightly downwards, otherwise the goo may flow into the instrument itself, creating other problems.

After a few minutes of rotating and squirting, the goo cleared. I then turned the output shaft pointing upwards and dropped some Q20 oil into the input. By this time I could easily rotate the input with a screwdriver.

Note: Lubricating with proper oil after cleaning is very important for lubrication because carb cleaner is not a lubricant.

Effectively the speedometer was now back to normal, ready to be replaced back into the instrument cluster.
I hope it will last a long time.

Checking the speedo drive on the front wheel, I realised that this unit was also not working properly. The seizing of thr speedometer prevented the speedo cable from rotating and caused damage to the nylon ring in the speedo drive. The steel tabs in the wheel hub had gouged a groove in the nylon (see picture)
Okey, easy to solve ... (remember, the same drive packed up in Jan'14.... http://bmwmccc.org.za/speedo-drive-failure )

I removed the front wheel and slightly bent the steel tabs in the wheel hub outward, 2mm on each tab. Note: Complete bending one at a time, to ensure that each tab was bent 2mm (and not one tab three mm and the other tab one mm...).

I inspected the speedo drive unit, which was fine except for the grooves made by the steel tabs. No work needed on the nylon drive itself. The outward bending of the tabs solved the groove problem.

 The lubricant was still fine. I re-fitted the drive, connected the speedo cable and all is back to normal!

BUT, the speedo needle was dancing with a slight twitch --- the cable was indeed damaged by the initial winding-up due to the seized instrument.

Cable Clinic in Parow repaired the cable (actually made up a new cable, using the original end fittings). Cost R136 incl. VAT  (what a bargain!)

Now all runs perfectly smooth and like new.

Some other comments.
1. If the speedometer on your bike starts to whine (some call it "screaming"), it is a sure sign that the bearing on the input shaft is very unhappy, worn and probably building up to seize. Take out the instrument, clean the input shaft (with carb cleaner as descibed above) and lubricate it with a light oil. Then put it back and check that the whining is no more.

2. If your speedo cable packed up, it may be that the speedometer input shaft does not rotate freely. Use a small screwdriver and check that the speedometer input shaft runs easilly. A replacement speedo cable will not last long if the speedometer input shaft is sticky and remains un-repaired.

3. The fact that the speedo drive is designed the way it is (steel tabs driving nylon tabs) appears to be a very purposeful and clever design.
Being slightly "soft" and easy to cut a groove in the nylon tabs, it actually protects the speedo cable and the speedometer instrument.

4. Something that I considder not a good design: the distance counter inside the speedometer is driven by a very timid entry gear.
If this gear wears out or is damaged by a sticky distance counter, the distance counter stops working.
Repair of this would be a major challenge:

a) where to get such a gear and

b) how to physically remove and replace it.
The entire speedometer is positively hostile to dis-assembly by anyone less than an instrument technician.

Looking at the drivegear, I imagine that you could re-use the damaged gear by moving it axially by 5mm. But, in order to do this, you need to manufacture and fit new offset bearings i.e. do substancial surgery to the assembly.