Archive of BMW Motorrad Club Cape (2006 - 2019)

Ek dink ek kon myself baie geld gespaar het.

The speedometer on my 1150GS stopped working all of a sudden. With the odo now at 125000km, one can expect few components to give trouble.
I first tested the speedo cable (rotate the input side anticlockwise with an electric drill). The cable passed the test so the culprit was the speedometer drive on the front wheel. This was confirmed when I found I could rotate the speedo drive output shaft without any resistance.

Speedo drive unit
The agents quoted close to R1000 and delivery of "at least six weeks" (They do not keep stock of this component because there are very few requests for it. Yet the same guy told me they "sold the last one yesterday") I ordered one from Kingtek at just under R700, delivery a lot quicker, including Christmas delays.

While I had no speedometer, I used a printed sticker on the windscreen showing engine revs vs speed. Initially I used the cellphone GPS, but the sticker & revcounter proved to be more practical.

It is interesting to note that at 100km/h the engine speeds were 5000rpm in 3rd gear, 4000rpm in 4th gear and 3000rpm in 5th gear respectively.

This GPS arrangement did not work well in traffic. One has to take your eyes off the road too long to check speed. Plenty danger can develop in that short time.

Once the new unit landed, I fitted it and it works fine.

Afterwards I checked the old unit and then realised I could have fixed it quite easily, saving me the cost of a new unit.

The problem was that the tabs on the floating ring driven by the wheel hub made a shallow groove in the nylon sleeve that drives the worm gear to the speedo cable. The tabs started to run in this groove and stopped driving the worm gear. Also, the lubrication inside the drive unit was practically gone. I think the increased resistance due to poor lubrication expedited the failure.

I then realised that if I bend the two tabs outward as in the picture, they would grip again and would probably give me another 100000km.

The tabs are on the circumference of a floating ring. This ring can move axially inside the wheel hub. Looking at the depth (or shallowness if you like) of the groove, I think one should also insert a nylon spacer (eg nylon string from a weedcutter) behind the floating ring. This will move the tabs closer to the nylon geared ring.

Anyway, Geelkameel now runs with a new speedo drive and I have one in spare, plus the knowledge how to save money next time.

IMPORTANT NOTE:

500km later the speedo stopped working again! check this out:

http://www.bmwmccc.org.za/speedometer-stopped-working-frozen-solid

Moral of the story ... find the root cause for the failure and fix that as well!!