Speedo issues on my '74 R60/6

[DS74BMW]

I was just reading Karsten's "odometer issues" thread, as my trip odometer won't reset [sort of], the speedo needle will fluctuate wildly above 60 [then "settle down"], and the tach needle is not steady[200-300rpm wavering].

When I test rode, the speedo fluctuated above 30[would read 60-80, then "settle"], so the seller said he'd fix it. When I loaded it into the truck to bring home, he said he lubed the cables and opened the instruments up and cleaned dirt out, and it worked fine. After getting home, a trip down my street up to 30, worked fine [the trip meter wouldn't reset, though]. After putting tags on it, I went for a 40 mile trip. At some point, the trip meter reset itself to zero during this ride [and will not reset now], and counted properly, but the speedo above 60 would waver wildly[100-130], swing to zero, and then indicate properly. This happened 3 or 4 times in 40 miles.

I linked to Overseas Speedometer on Karsten's thread, and a note under BMW mfr said to disconnect the cable asap, as it was about to crash. I will do this, until I can resolve. Also, not all the instrument lights work, so I will try to resolve all this at same time.

I saw a site a week ago about disassembling these[R60/6] instruments for repair, but cannot find it again. Perhaps sending it to Overseas Speedo, but I like to do my own work as much as possible. I still do not have my ordered Clymer manual, so a site would help at the moment.

 

[20774]

This should provide some insight on disassembling the speedo/tach unit:

http://www.pbase.com/dwerbil/1978_r1007_odometer_repair

First thing I would do it buy a new cable. Likely you need it and lubing the cable is typically not done as most BMW cables are Teflon lined and lubing only ends up attacting dirt. What's probably happening is a stranded of the wrapping on the steel cable has come loose and is catching/releasing in certain situations causing the flucuations.

 

[tvrla]

It could be the cable, but wouldn't count on it. Far as I know, teflon is only in the control cables, not the tach and speedo.

These units need to be cleaned and lubed just like watches, otherwise the bearing points wear quickly. When it gets bad, the needle shaft grabs and slams the needle against it's stop and breaks it. The shaft then turns and wads up the spiral spring. And then the shaft bearing surface breaks off, and you're into some major parts.

Better to clean and lube while it's working, before it malfunctions!

 

[DS74BMW]

I will check the tach and speedo cables, and leave the latter disconnected.

The above link is for a '78 R100/7; is there much difference from my '74 R60/6? A good link and photos - got it in favorites for ref.

 

[20774]

The above link is for a '78 R100/7; is there much difference from my '74 R60/6? A good link and photos - got it in favorites for ref.

I've never seen a specific link for a /6...they should be reasonably close, expect that your tach is driven by a cable whereas the /7 tach is electroncially driven.

 

[barron_williams]

Your 1974 should be very close to the pictures in the link above. It isn't too hard to take the instrument cluster apart. There will be like four layers of parts, each with their own screws. I usually take a sheet of paper , draw the oval shape of the housing, and as you take the screws out, place them on the drawing in the position they came from. As you get to the next layer, draw a new oval, put the screws on it in the position they came came from, and so on. Assembly is in reverse order.

That will get you the tach and speedo assemblies out, as well as let you look at the plastic sandwiched wiring "board". The board may need to be replaced. There are two types of bulbs. Part numbers for the board and bulbs can be found in any of the online parts fiches (like Max BMW). One note - the bulb holders just pull out (gentle wiggle). I seem to remember you have to remove the high beam light before you can get to something else. You should be able to get all the lamps working fairly easily by replacing the wiring board and lamps as necessary. Pretty simple and straight forward.

The tach and speedo look to be a slightly more complicated project. I've not had to go into the instrument clusters themselves. But, there is a good tutorial on fixing the odomenter slip on the airheads homepage under tech articles. Some years ago, a friend of mine sent his instruments to Palo Alto Speedometer (advertise in the BMW MOA Owners News) and they came back nice and fresh with bright orange needles, but it cost a couple of hundred dollars.

Barron

 

[DS74BMW]

Thankyou, all! The above insights will be a great help!

I will post what I find, as someone else may have a similar problem.