I have just purchased an 1984 K100RS last Thursday, the plan is to clean it up and put it on Historic Rego.

There's not a lot to do as the bike is not too bad, a bit rough round the edges but it's all there and it's all original from looking it over.

I've pull the instruments off to replace the Hazard switch and trip meter knob which I broke straightening the faring mount(yes I know I should have taken them off first)I was going to buy a second cluster for parts but they do seem a tad on the expensive side so I decided not to, but what I found while searching was the amount of different pins numbers there are between the models, none of which match mine with 23 pins and that's in the cluster and on the connecters from the ECU itself so it must be original, right.

It has no extras that I can see, it looks like a basic K100RS, it's even the Pre 95 unleaded model, so does anyone know why it would have 23 pins in the connections.

Yours should have 24 pins.  Can you post a photo to show your gauge cluster?

For reference here is the wiring chart for an early model instrument cluster:


All BMW model clusters had pin 20 unused.  The only difference between an early model and late model cluster plug was Pin 8.  It's populated on early models and not populated on late models

For an 84 K the cluster you buy must show 2 petrol warning lights and petrol pump signs on the left speedo side. One orange for 7 litre and one red for 4 litres. These are used only up to early 85. They are used where the gas tank is bolted at the rear, also you will see that passenger seat handles are in the seat.

Later clusters only have a single petrol pump sign on the speedo side with a red 5 litre warning.

I've checked again, has the 2 warning lights, and 23 pins in the cluster and the plugs, it won't let me post photos keeps saying post too long.

OK if you count the unused pin 20 which is not actually there, then yes it has 24 pins.

Also there's no bulb in 4L warning light and I suspect the bulb is blown in the 7L light.

Bazza wrote:I've checked again, has the 2 warning lights, and 23 pins in the cluster and the plugs, it won't let me post photos keeps saying post too long.

Check this out for posting pics https://www.k100-forum.com/t998-posting-pictures-and-movies 
You can't just copy paste a picture to a thread.

test

test

Yes, your plugs are completely normal.  Pin 20 has a blanking plug inserted into the hole so it looks contiguous with the housing, but there is a hole in that position.  Correspondingly, there is a pin removed in position 20 on the circuit card receptacle.   Late model gauge clusters had round sockets and pins, whereas yours are square.

The missing pin is polarisation so that you insert the correct plug onto the correct pins.

For interest, here is a picture of the back side of a late model K75 gauge cluster with round pins.  Note that Pin 20 is also missing on this model.

Cluster

Is your bike ex-police?  That looks like a police gauge cluster with the enhanced accuracy speedometer.

FYI, Google album of a ground-up restoration of a 1986 K100TIC Victoria Police bike:  https://get.google.com/albumarchive/107132141978533857555/album/AF1QipMgEwm1AOJ_Lfi-rblq61tdW27d2weuUIpY_Ef0

robmack wrote:Is your bike ex-police?  That looks like a police gauge cluster with the enhanced accuracy speedometer.

FYI, Google album of a ground-up restoration of a 1986 K100TIC Victoria Police bike:  https://get.google.com/albumarchive/107132141978533857555/album/AF1QipMgEwm1AOJ_Lfi-rblq61tdW27d2weuUIpY_Ef0

The bike isn't, but looks like the speedo is, there ya go I didn't even notice

Thanks guys for your help.

One more question about the cluster, how do the globes come out, I tried pulling them out but they won't budge and I didn't want to force them out in case I broke them, one is missing.

The Haynes manual only covers putting them back in and mentions that the cap/cover needs to be replaced.

robmack wrote:Is your bike ex-police?  That looks like a police gauge cluster with the enhanced accuracy speedometer.

FYI, Google album of a ground-up restoration of a 1986 K100TIC Victoria Police bike:  https://get.google.com/albumarchive/107132141978533857555/album/AF1QipMgEwm1AOJ_Lfi-rblq61tdW27d2weuUIpY_Ef0

WOW that's a bloody good resto.

The bulbs are friction fitted into square holes so they yank straight  out.  Pull harder on the black plastic sockets than you are doing now; maybe even wiggle it from side to side slightly.  When the bulbs come out, they may pull the flexible circuit card out of the hole.  Just put it back into the hole when replacing the bulbs.

robmack wrote:The bulbs are friction fitted into square holes so they yank straight  out.  Pull harder on the black plastic sockets than you are doing now; maybe even wiggle it from side to side slightly.  When the bulbs come out, they may pull the flexible circuit card out of the hole.  Just put it back into the hole when replacing the bulbs.

Brilliant thanks, any idea where I can get the black plastic cover.

Bazza wrote:Brilliant thanks, any idea where I can get the black plastic cover.

Are you referring to the black plastic sockets into which the bulbs plug?

And when you put the plastic circuit back into place make very sure the little copper flaps are hanging down into the hole.  If you don't make sure of this, the bulb won't work.  The knucklehead who works on my bikes in my garage discovered this the hard way.

RicK G wrote:Check this out for posting pics https://www.k100-forum.com/t998-posting-pictures-and-movies 

If that tutorial doesn't work for you, try this one.

Thanks everyone I have managed to get the bulbs out, did a test and the bulbs seem fine, anyway I've ordered the caps for the bulbs and got some bulbs form supercrap but I 've got 5w instead of 3w, will these work as I know how fussy BMs are with bulb sizes.

5w just a bit brighter. The OEM green bulbs are green because they are wearing little green condoms. These are removable and can be refitted to LED's.
Regards Martin.

MartinW wrote:5w just a bit brighter. The OEM green bulbs are green because they are wearing little green condoms. These are removable and can be refitted to LED's.
Regards Martin.

Thanks Martin, it's all coming together, got a hazard light switch as the old one had been cut off and a new trip metre knob.

MartinW wrote:5w just a bit brighter. The OEM green bulbs are green because they are wearing little green condoms. These are removable and can be refitted to LED's.
Regards Martin.

You can also buy little green men bulbs online so they don't need condoms. Have no idea if they will reproduce though.

https://www.ebay.co.uk/itm/322824349542?hash=item4b29d4a766:g:zOIAAOSw8K5asZVL

Or use coloured led bulbs. Except the charge light bulb, it needs to be 3W. You can get one with a resistor in it to compensate for that.

+1 on the colored LED bulb replacements.  Try doing a search for "LED automotive instrument lamp replacements".  I get mine from Super Bright LED's.

https://www.superbrightleds.com/

I use these for backlighting the cluster, you can have some fun with matching the color of your bike:
https://www.superbrightleds.com/moreinfo/wedge-bulbs/194-led-bulb-3-smd-led-miniature-wedge-retrofit-car/3551/7578/#tab/specifications

These work for the idiot lights.  The lower lumen output is good to reduce glare at night.  Use the 90 degree beam angle:

https://www.superbrightleds.com/moreinfo/wedge-bulbs/194-led-bulb-1-led-miniature-wedge-retrofit-car/197/852/#tab/specifications

Even with the lower output, the low fuel and high beam indicator lights can be nasty at night.  I mask off some of the indicator lens with a piece of black tape that has a 6mm hole punched in it.  It's still visible in daylight, but won't blind you at night.

As mentioned above, leave the bulb for the Battery idiot light.  It does the best job of controlling the alternator output.

If you go with LEDs, then polarity matters.  Here is a photo of the manual Frankenduck produces for his kit which shows the polarity for LEDs in different positions.

That's what is nice about the ones I linked.  They're non-polarized. 

Most automotive retrofit LED lights are non-polarized these days.  This is especially true of the wedge base models used in instrument clusters and interior lighting.

LEDs... no, no and no. No. Definately NO. The worst ride I have ever had on a K was in very heavy rain on a motorway with green LEDs providing the backlighting. That was bad enough - way, way too bright for those conditions. The uplight was seriously distracting. Then the fuel lights came on in turn and the resulting glare was utterly horrific to the point where the combination of LEDs and rain on my visor was almost literally blinding. I could not find a position where I could use the chinguard as a light shield without getting rain driven down my neck. As soon as I got home the LEDs went into the bin and I refitted the original tungsten bulbs. Furthermore, I modified the PCB so that I could dim the fuel warning lights at night.

No way am I ever going there again.

Dai, don't go by the exposure of the photos I posted.  That is the result of the exposure control on my camera.  The backlight in the clusters is low enough that in order to get it to show I had to increase the exposure to where the idiot lights flared. 

Actually, the illumination with the LED's I linked is very close to the OEM incandescent lighting.  The only problem I had was with the high beam and low fuel indicators.  As I mentioned earlier, a mask with a 6mm hole reduces the glare to a comfortable level while still making the indicator visible.

I have had led lights in the K1100 but hop regularly from that to the RT and RS that have the regular incandescent bulbs. I dont have any glare issue at all so maybe different type leds. I plan on making them all led as I liked the light colour and do a lot of night rising..

I believe it is a typo, but I think your way of saying "night rising" instead of "night riding" is very poetic.
It conjures up the vision of K100s rising up everywhere to take over the highways and byways in the deep dark of night!

robmack wrote:Is your bike ex-police?  That looks like a police gauge cluster with the enhanced accuracy speedometer.

FYI, Google album of a ground-up restoration of a 1986 K100TIC Victoria Police bike:  https://get.google.com/albumarchive/107132141978533857555/album/AF1QipMgEwm1AOJ_Lfi-rblq61tdW27d2weuUIpY_Ef0

Robert, how do you get your aluminum bits so clean and shiny? Is that done with vapor blasting? Do you treat them in some way afterward to avoid oxidation or just let them weather naturally?
Mike

Shep wrote:I believe it is a typo, but I think your way of saying "night rising" instead of "night riding" is very poetic.
It conjures up the vision of K100s rising up everywhere to take over the highways and byways in the deep dark of night!

Trying to work out if you are a member of the Grammar Police or the Oscar wilde School of English or both. I decided to leave the typo unedited as your response is too good!!
 

I'm about to put the instrument cluster back together but the trip meter knob has me stumped, what's order to put it back in.

Looking at it, it's knob, the thing that thing in the cover, washer, spring, washer, C clip!!

Put the knob etc into the housing then pull it outwards and jam something about the thickness of a matchstick to hold it out, put the cover back on and remove the thing so the knob goes back in to mesh with the innards.