I've had a recent problem where I've lost the speedometer and tachometer, now I've got several sets of clocks and 2 k100's and a k75 that the clocks have been tested on. The Tachometer works on all and so does the speedometer so I know that's not the problem.

However on my daily k100 1984, I've lost the speedometer and tachometer as in the needles don't move at all. I've tested the power connection to the speedometer pulse wire that connects into the final drive and there doesn't seem to be any power at all. At the moment I'm pretty stumped on what to check next. All earths that I know of (under the tank, back of the fuel rail, to the left of the bike from the battery) are all clean. The pesky starter motor is clean and the bushes were replaced two months ago.

My only idea at the moment is the cable that goes straight into the clocks itself which is part of the main harness. Does anyone happen to know which wire it is for the speedometer and tacho.

Or any other suggestions on where to look next; if it was mechanical it would be easy to sort with it being electric I'm stumped.


EDIT>>>>

I've also lost the right hand indicator front and rear everything else works, locally can't get DEOXIT so I've had to order it online. I've been using normal electrical cleaner for now.

When you turn the key without starting, does the charge indicator work?
It's the black wire, coming from the alternator to the dash.
Connected when you turn around the breadbox, it's pin 9, the fourth from left under.


(It's Dutch, but in case I can translate...)

Other possibility is, that the brushes of your startermotor are too far gone.
At 6 or 7 mm they go bad, and give these kinds of problems.

Well I've found my problem seems to be the plastic connector is brittle and falling apart. With this being a BMW specific connector it looks like I may have to go down the route of a new loom or replacing the connectors with good decent ones.

Ow dear, the good old flat pins, haven't seen them since my K100 years ago.
Maybe find replacement in big electronics online, such as Conrad, Reichelt, etc.

Not BMW specific and not that expensive to replace.

https://uk.rs-online.com/web/p/pcb-connector-housings/5091708
https://uk.rs-online.com/web/p/pcb-connector-contacts/5091994

You do have to buy more than you need, but last time I bought some I was able to offset the cost by passing on sets of connectors + pins to other members on the forum.

Thank you Dai, with BMW and the little plugs that are on the end of the ignition for example; mistakingly I assumed they were specific.

I'll order some then help anyone out in the UK if they need to replace there's.

Arlina wrote:When you turn the key without starting, does the charge indicator work?
It's the black wire, coming from the alternator to the dash.
Connected when you turn around the breadbox, it's pin 9, the fourth from left under.

FYI: The wire from the alternator to  the cluster is blue, not black.

Dai; thanks, didn't know there was a replacement. No need for me, just learning

Duck; got it from the diagram from Bert, that one is black for the K100.

It's blue for all of the classic K bikes:

http://www.kforum-tech.com/Downloads/electrical/diagrams/interactive_diagrams.htm

Bertrand say black  

I'm going to argue with both of you: the two wiring looms I stripped were black/blue to the tachometer. One was an '83 K100 and the other an '86 K100. Haynes shows black/blue too but (and I'll get in first) their reliability is sometimes suspect.

I have some wiring harnasses here, will check tomorrow with daylight.

I remember on my K100RT 1986 it was black.

Arlina wrote:http://www.kforum-tech.com/Downloads/electrical/diagrams/interactive_diagrams.htm

Bertrand say black  

That diagram indicates Black/Blue.

Laitch wrote:

Arlina wrote:http://www.kforum-tech.com/Downloads/electrical/diagrams/interactive_diagrams.htm

Bertrand say black  

That diagram indicates Black/Blue.

Black/blue is from the coil to the tacho.
Black is from the alternator to the charge indicator/12V to speedo and tacho.

Arghhhh!!!! I just re-read Duck's answer and wondered where the hell I got sidetracked. Yes, the alternator control wire is blue. Go take a look at the back of the alternator - it's very visible.

Sorry Duck....

Got my eye on it

Bert F..cked up!
I can see my mistake: On the original black and white schematic, the color is marked "BL" which is Blue or Blau in German.
I simply mixed my English and German and interpreted BL as Black.

But for sure we use your diagrams
(even though we lost many bikes due to the black or blue wire..... )

Dai wrote:I . . . wondered where the hell I got sidetracked. . . .

I don't know about you but I got distracted by the thread's title and and a flare-up of cabin fever.

Crazy Frog wrote:Bert F..cked up!
I can see my mistake: On the original black and white schematic, the color is marked "BL" which is Blue or Blau in German.
I simply mixed my English and German and interpreted BL as Black.

As I'm sure you know, black is schwarz (SW) in Cherman.

I finally found my original files and made the correction on the main diagram.
Looking at what I made 10 years ago was a big project! But as people use it, it wasn't wasted time.

Hi Bert, 

Just want to say a huge thank you for the wiring diagrams. I'm new to bricks and this forum, I thought Gregory's wiring was the easiest, until recently when I found yours. These diagrams are a big time saving tool and a huge asset for understanding.

Thanks daveyson.
I made them when I was trying to understand the K bikes electronic.
Now, I use them all the time.