BMW K bikes (Bricks)

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robmack

robmack
Life time member
Life time member
I reverse engineered the LCD Gear Indicator board as part of my project to build a drop-in replacement for the LCD.  I then proceeded to reverse engineer some other boards and draw their schematics, as well as collected schematics from other sources and re-interpreted those drawings.  The flasher unit schematic is not my work; it is available online.  I'll add more as I convert the BMW OEM circuits into schematic drawings.

GPI  This is the board that is located in the OEM cluster underneath of the Tachometer on the right side, containing the LCD that shows the currently selected gear:
REFERENCE: BMW Instrument Cluster schematics Xfsvnq


REFERENCE: BMW Instrument Cluster schematics 270-041117084711
Large Image

Basic Circuit Description
Power is supplied through pin 15 (+12V) and 31 (Ground).  A diode, V7, ensures that reversing the polarity of the power will not destroy the components on the board.  VIN is fed to the Start Enable circuitry and to the regulator V9.  Regulated VDD supplies the chips with power as well as other parts of the circuit.

The TGPI switch connects to A, B and C inputs.  Diodes, V3, V4 and V5, form a neutral detect feature that operates the Start Enable circuitry.  The three transistors, V8, V9 and V10, creates a +12V signal on the output, LEERL, that drives neutral and the starter relay.  Diodes, V1 and V2, detect when the selected gear is higher than 5th and will send a signal to IC1 to blank the LCD display.  IC1 decodes the inputs and displays a digit on the LCD via PAD-A through PAD-G.

IC2 is an oscillator that creates a high power signal that powers the LCD.  This signal is output on PAD-COM and consists of a 67Hz 100V 50% duty-cycle squarewave.

Speedometer and Odometer
This board is located in the OEM gauge cluster and converts the output from the speed sensor in the final drive into a signal that drives the speedometer servo motor.
REFERENCE: BMW Instrument Cluster schematics 68
REFERENCE: BMW Instrument Cluster schematics 81


REFERENCE: BMW Instrument Cluster schematics 270-191117085105
Large Image

Tachometer
This board is located in the OEM gauge cluster and converts the output from coil #1 into an RPM reading on the tachometer gauge.
REFERENCE: BMW Instrument Cluster schematics 25


REFERENCE: BMW Instrument Cluster schematics 270-161117215844-8181222
Large Image

Early Fuel Level Sensor (4L/7L lights)
This board is located in the OEM gauge cluster for the early K-bikes prior to 1985.  The fuel sensor was a pair of thermistors.  These devices illuminated a lamp in the OEM gauge cluster that showed when the fuel remaining in the tank was 7 litres and 4 litres.  This is an interpretation of a schematic posted by Bert Vogel on K100-forum.
REFERENCE: BMW Instrument Cluster schematics 22810


REFERENCE: BMW Instrument Cluster schematics 270-161117215842-7951388
Large Image

Flasher Unit
This schematic was posted online at the K100-forum and I am including it in this collection.
REFERENCE: BMW Instrument Cluster schematics 14


REFERENCE: BMW Instrument Cluster schematics 270-161117215846-8192362
Large Image

Clock
This schematic is of the clock in the OEM dash.  To test that all segments of the display are working, press both switches together at the same time.
All segments will light up.  When the switches are released, the clock will reset to 1:00.   One complaint of the clock is that it only shows 24 hour time. To get the clock to display 12 hour time, use an Xacto knife to cut the trace at pin 22 (labelled "S5" in the schematic) and then take a 30GA solid wire and join S5 to VIN.  This will change the clock to display hours between 1-12.
REFERENCE: BMW Instrument Cluster schematics 19   REFERENCE: BMW Instrument Cluster schematics 20


REFERENCE: BMW Instrument Cluster schematics 270-211117200828
Large Image

Bulb Monitoring Unit
This board is located in the relay box.  It's purpose is to monitor incandescent bulbs in the rear tail of the motorcycle, the brake light and running lights as well as the brake switches themselves.  If any bulb or any switch is defective, the BMU will illuminate an indicator on the dash. Since there are no parts identification silk screened on the board and my schematic makes reference to part identifiers, I arbitrarily assigned reference numbers to parts on a photo of the board. This photo helps to show the location of the various components and references them by their part identifier on the schematic.
REFERENCE: BMW Instrument Cluster schematics 270-030219185849

REFERENCE: BMW Instrument Cluster schematics 270-270119202315
Large Image



Last edited by robmack on Mon Feb 18, 2019 9:52 pm; edited 11 times in total


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

Dai

Dai
Life time member
Life time member
You learn something new every day. I had no idea that you needed an oscillator to drive the LCD. I'd assumed that they were a bit like LEDs; add power and away you go.


__________________________________________________
'83 K100 upgraded to K100RS spec, '87 K100RT
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California
    

Ringfad

Ringfad
Life time member
Life time member
Thanks for sharing. This is great work.

Have you ever done one for the speedo amplifier ?


__________________________________________________
REFERENCE: BMW Instrument Cluster schematics Ir-log10

   ;BMW; K100RS Style Black 1987 105K Km     ;BMW; K1 Black 1993 51K Km     ;BMW; K1100RS Red 1993 70k miles (exiled in Alicante at the moment)  ;BMW; K100 16V Black (ex ElectricMonk)  ;BMW;  K1100LT (Swiss) soon to be an RS
    

robmack

robmack
Life time member
Life time member
@Ringfad wrote:Thanks for sharing. This is great work.

Have you ever done one for the speedo amplifier ?
This is on my TODO list.


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

charlie99

charlie99
VIP
VIP
fantastic work yet again rob

and thanks for sharing


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OREFERENCE: BMW Instrument Cluster schematics Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

6Back to top Go down   REFERENCE: BMW Instrument Cluster schematics Empty Instrument schematics on Fri Mar 08, 2019 6:36 am

WarrenD

WarrenD
active member
active member
I'm trying to share a link of a drawing I made. e.g.obmacks bits connect. Does this link work?
http://forum.kforum-tech.com/members-upload/uploads/K_Instruments.pdf


ie Can this put in the downloads dept?
I found this but doesn't work?
https://www.k100-forum.com/f3-downloads

    

Ringfad

Ringfad
Life time member
Life time member
I can download with the link provided.


__________________________________________________
REFERENCE: BMW Instrument Cluster schematics Ir-log10

   ;BMW; K100RS Style Black 1987 105K Km     ;BMW; K1 Black 1993 51K Km     ;BMW; K1100RS Red 1993 70k miles (exiled in Alicante at the moment)  ;BMW; K100 16V Black (ex ElectricMonk)  ;BMW;  K1100LT (Swiss) soon to be an RS
    

Dai

Dai
Life time member
Life time member
One more post needed, I think.


__________________________________________________
'83 K100 upgraded to K100RS spec, '87 K100RT
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California
    

gabriel

avatar
Platinum member
Platinum member
Hi

I have a question about my speedometer. 1984 k100.
Tachometer is working.
Speedometer and odometer not working.
Speedometer became erratic just before it stopped working.
All internal components seem to be ok..
Speedometer face is fine, speedometer needle moves freely on the shaft.
Not certain how to approach this problem.
Incredibly frustrating.

Thanks

Gabriel.


__________________________________________________
;BMW; 1984 BMW k100..frame number 6228?
    

duck

duck
Life time member
Life time member


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

ivicenzo

ivicenzo
New member
New member
Thanks for sharing, very useful indeed.
I had a problem last year and it took 2 batteries, one alternator rebuilt and some other stuff before unplugging the ABS that was the root of the problem. One pump was defective and it damaged the instrument cluster, battery and alternator. Installed a used one I bought on Ebay but the odometer doesn't work (maybe because it is on miles and my bike is on kms). Anyway, once the ABS was unplugged with the new speedo everything started working. I switched back to the old speedo and it doesn't charge the battery.

Anyway, the 2 questions are: 1. Can the odometer be fixed? 2. Any idea which circuit is responsible for draining the battery? Thanks,

Thanks,

Vin

    

WarrenD

WarrenD
active member
active member
Check all the connections and the gears. Facebook Ricardo palao for new gear sets.  The alternator needs the charge bulb in the circuit to work. If the bulb is blown it of course will not light nor will it charge.

    

Exsna01

Exsna01
active member
active member
I will try this also as my speedo is intermittent, thanks much for this help. Lon

    

Two Wheels Better

Two Wheels Better
Moderator
Moderator
@WarrenD wrote:Check all the connections and the gears. Facebook Ricardo palao for new gear sets.  The alternator needs the charge bulb in the circuit to work. If the bulb is blown it of course will not light nor will it charge.
This is true with Airheads but not with K bikes, in my experience. There are no idjut lights on Big Block, in fact, no instrument cluster at all, and she cranks out all the voltage juice she needs to keep the battery charged without a bulb (or LED) in the circuit.


__________________________________________________

Sometimes I lie awake at night, and I ask, "What can I do to keep my life from going by so fast?" Then a voice comes to me that says, "Try slowing down at the corners." 

~Charlie Brown

1970 R60/5, '77 R75/7-R100, '85 K100'87 K75C, '87 K100RS, '93 K11-K12 Big Block, '93 K1100RS, '95 R100-Mystic, '96 K1100RS, '98 K1200RS, '00 K1200RS, '02 K1200RS, '03 K1200GT, '04 R1150R'04 R1150RT, '05 K1200S, '06 K1200R, '07 K1200R, '09 K1300GT & 2013 R1200RT-Polizei  - Beemers owned still or sold.

    

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