Odometer adjustment

[szabgab]

Dear all,

I have a '87 K75S that is coming together nicely (meaning it is quieter more economical, less shaky and less noisy than it was, when I have bought it). There are some cosmetical things, I am finally addressing, one is the cracked speedo cluster with a non working digital clock. Also recently, in this crappy cold humid weather the cluster started to steam up pretty badly and the gear indicator has gone all crazy, but we have discussed that before. I have taken the swingarm off again, dried and sealed the switch, but the indication was just as wonky, so I have done a test, I should have done in the first place and checked the connector side - basically grounding the various cables, and guess what, the indication is just as wobbly, so it is the cluster, that is misbehaving.

Anyway, to make my rant short, I have decided to retire the old cluster and get a "new" one from a low mileage cafe racer build. I have opened the new cluster to clean the connections, seal the face as a precaution, adjust the speedo and also adjust the odo reading, as this one is showing probably the third, what is the actual mileage of the bike. I have done everything except the odo adjustment, I have taken the mechanism off, taken the gears off, the magnet off, the daily tripmeter off, but I could not get the shaft off with the small white positioning gears. Is there a trick to do that? I am sure, it is doable, as BMW and various mechanics would adjust a new cluster to match the old one, but how to get about it?

Thanks!

Gabriel

[Chaos]

my memory is foggy but it I remember holding some spring with a small screwdriver or moving the wheels over to one side so they would rotate freely.  I was able to figure it out by trial and error, knowing it is doable is half the battle, good luck

[Martin]

In order to stop the instrument cluster from fogging up BMW installed two material covered vents on later clusters. I've also heard that some owners put packs of silica gel in their pods to absorb any moisture. Apparently any moisture absorbed by the gel packs would dry up as warmer weather was encountered.
Merry Christmas regards Martin.

[Chaos]

I had an old unit I picked up for the gears, re-figured out how to adjust the odometer.  With a dental pick or small screwdriver, force the white gear to the right, you can then spin the number wheel directly below it.  1st photo I could adjust the 100,000 wheel, 2nd photo I could adjust the 1,000 wheel.  You need to push the white gears pretty hard and wiggle the number wheel to get it freed up.  Also make sure they all park neatly in a row or your numbers will look uneven.  This was with the 4 plastic gears off, don't think that matters though

[szabgab]

In order to stop the instrument cluster from fogging up BMW installed two material covered vents on later clusters. I've also heard that some owners put packs of silica gel in their pods to absorb any moisture. Apparently any moisture absorbed by the gel packs would dry up as warmer weather was encountered.
Merry Christmas regards Martin.

Martin - the silica gel idea is a neat one, the new cluster has got those vents installed, but for a good measure I might throw in some of those sachets too

Merry CHristmas to you too!

[szabgab]

I had an old unit I picked up for the gears, re-figured out how to adjust the odometer.  With a dental pick or small screwdriver, force the white gear to the right, you can then spin the number wheel directly below it.  1st photo I could adjust the 100,000 wheel, 2nd photo I could adjust the 1,000 wheel.  You need to push the white gears pretty hard and wiggle the number wheel to get it freed up.  Also make sure they all park neatly in a row or your numbers will look uneven.  This was with the 4 plastic gears off, don't think that matters though

Chaos, this is great thank you! So there is no harm done, if you force those white gears to the side?

Thank you and merry Christmas!

[Chaos]

Chaos, this is great thank you! So there is no harm done, if you force those white gears to the side?

Thank you and merry Christmas!

No, it's pretty robust.  I did a replacement cluster decades ago and it worked until last year when the gears dissolved again.  You're essentially taking all the slack out of the spacing and concentrating it at one point.

[szabgab]

Oh this worked like a charm... For simplicity I have adjusted only the 10.000's, but it was easy enough, when I have got the hang of it...

On another note - whilst having the cluster apart I have noticed the ABS symbol near the low fuel light and that got me thinking - the whole unit came off a bike that was an ABS equipped model, will that cause me any trouble? What I mean, I know, people have problems with blinking ABS and bulb monitor lights, if the system is malfunctioning.  ABS light is easy enough, I take the bulb out, but I think the bulb monitor is very convenient and would hate to get rid of it. Is the blinking etc. governed by the cluster, or is that some feature of the ABS system itself?

Thank you!

And a Happy New Year to you all!!   

[Laitch]

No trouble will be caused by your moto's having an instrument cluster with a bulbless, vestigial ABS warning indicator when your moto doesn't have an ABS system. The bulb monitor will still warn of defective bulbs regardless of the presence of the system. Remove a turn indicator bulb and prove it to yourself. One caution: there is no bulb monitor monitor to monitor the function of the bulb monitor—unless you appoint yourself as the monitor.

Happy New Year.

[szabgab]

there is no bulb monitor monitor to monitor the function of the bulb monitor—unless you appoint yourself as the monitor.

:D

So I have decided to take half of the bike to pieces to access the old cluster, funny how many plastic bits have to come off for that. Unfortunately my connector is a different type, the new cluster has got round pins, whilst the old one has square ones (with the corresponding square holed connector). Probably I could force the connector on the new round pins, as the difference is not large and probably there is enough flex in the holes, but would that hold up? Do I introduce a new source for oxidation to build up?

[Laitch]

. . .my connector is a different type, the new cluster has got round pins, whilst the old one has square ones (with the corresponding square holed connector).

Surprise!  :birthday:

Read this saga. One of the reasons why DeoxIT is recommended as an electronic component cleaner is its oxidation prevention components. Look for it in a music shop that sells amps and control boards for Techno and Thrash-metal musicians.

[szabgab]

OK, so everything is back on the bike, and for the record - if anybody is attempting a similar transplant - once in a life round peg in a square hole is a non-issue, as the holes have got enough flex and the plastic mouth is wide enough to accommodate the round pins. There is one extra pin on the back of the cluster compared to the old one, it must be the ABS light, as the ABS light does not come on at all and the cluster behaves just like the old one was. I could not ride the bike as yet, but the stationary test showed as everything functional, bulb monitor goes out if brakes are depressed, gear indicator and neutral light shows correct values, clock and idiot lights do work, even the choke light does (although I feared losing that functionality), however I did not test the gauges or the low fuel warning as yet.

[szabgab]

Riiight, so I have tested the new unit for speed, and it needed some adjustment to show 61KPH. Whilst doing that, I have realised, my old cluster's speedo and the new do differ slightly. The old speedometer unit's gears were tied down with a plastic cover and two machine screws. There was also a plastic screw pushing on the end of the main odometer shaft. The new one does not have that plastic screw, only the thread. Now the plastic screw could have been omitted later, as looking at various pics on the web I do not see it, but does anybody know, if that is something, that has been removed by a PO and the odometer will go all crazy without that part?

Thank you!

[szabgab]

Oh dear, the story continues...

I have taken off and put back the cluster a few times to check for the accuracy and adjust it subsequently and on one occasion I misaligned the pins... The lights turned on and I could not switch off any of them, till I did not remove the cluster. After this everything was working just fine, but the triangle warning symbol stays on solid, no matter what I do.

I have read through Frankenduck's description about speedo calibration, and he has written -
Another Warning: If, when testing, you misalign the connector pins on the instrument cluster when hooking it up you can fry your $75 Bulb Monitor Unit in the relay box. so I guess that is exactly what happened to me. How to tell, if indeed the BMU has gone tits up, and what to do about it (replacement or repair?)...

Thank you!

[Laitch]

Oh dear, the story continues...but the triangle warning symbol stays on solid, no matter what I do.

What have you done? Have you checked for a blown taillight or brake light?

[szabgab]

What have you done? Have you checked for a blown taillight or brake light?

Hi Laitch,

Yes,  I have checked the obvious things,  brake lights,  running lights,  low beam, high beam,  although that should not trigger it.  It was working yesterday,  and it does not now,  and I had this mishap in between so I can not think of anything else...

[szabgab]

Hi Laitch,

Yes,  I have checked the obvious things,  brake lights,  running lights,  low beam, high beam,  although that should not trigger it.  It was working yesterday,  and it does not now,  and I had this mishap in between so I can not think of anything else...

I have found a great article at http://bmwmotorcycletech.info/k-hints.htm but it does not have any info on how to test the unit itself, if it is indeed faulty. Also I am not sure, what Frankenduck meant by frying the unit and he is not an active member anymore... Did anybody else had to dig into their BMU or has done something stupid, as I did by misaligning the pins?

[szabgab]

OK, as nobody chimed in, I have taken the BMU out of the relay box. It smelled burned electronics, so I commenced on opening up the unit. Upon further investigation it turns out, the BMU is indeed fried nice and proper. There is a transistor, resistor and a capacitor connected to the K leg of the unit, that is supplying the delta warning light with electricity. Now that I have connected the cluster all wrong, the K leg must have gotten raw 12 volts from the battery and that blown up the transistor and melted the resistor. The transistor must have killed itself remaining shorted, so in order to relieve the bulb in the cluster I have removed the transistor, thus cutting the electricity supply. For now it is like that, current flowing through the legs, but not triggering the delta light at all. Eventually I will replace the transistor and the resistor, as they cost pennies.

For future reference: the transistor is a BC517, the resistor a 100K Ohm one (although as you can see from the pics, there is no ceramics left on it, so I measured it rather than read the various colour codes, which would have been preferred...