BMW K bikes (Bricks)

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1Back to top Go down   Other speedometer Empty Other speedometer Fri Nov 05, 2021 7:30 am

ouafnico

ouafnico
active member
active member
Hi all !!

Before working on my K100, and cleaning wiring, I am testing the speedometer and the BEP 3.0 I received.

I did not buy a acewell speedo because of the cost, and buy a chinese speedo, technically "standard" to try first :
https://www.ebay.fr/itm/403176386765?hash=item5ddf2f70cd:g:rYkAAOSwSKBdnvgZ

It seems to have the same wiring, 3x3 connector, 3x2 for gears, 1x3 for speedo, but it got 3 standalone cables : red, black, and gray.

I tried to connect the BEP and the speedo, but the colors on cables on the 3x3 are not the same as acewell.

For example, to just power on the speedo, I had to connect :
- green on 3x3 to ground (seems standard)
- standalone black to BATT ! (WTF, why a black cable to 12V positive)

I got working :
- high beam light
- gears (on 2x3 connector)

Not working :
- battery signal
- turning (got problem elsewhere)

I can't test :
- speed and RPM (my K100 don't have oil actually)

I've checked a lot of pictures, schemes, found online, but it seems the colors on the 3x3 are completely messed up.

Anyone with a working speedo can share wiring schemes, others stuff how can help ?
I will put a scheme of what I got

Thanks a lot,

    

2Back to top Go down   Other speedometer Empty Re: Other speedometer Fri Nov 05, 2021 8:49 am

robmack

robmack
Life time member
Life time member
I wrote a manual for this family of gauges that might help.

- standalone black to BATT ! (WTF, why a black cable to 12V positive)
Because the gauge needs two sources of power, one switched and the other unstitched.  So there ends up being three wires for power.  Why black?  Maybe the manufacturer ran out of colours.


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

3Back to top Go down   Other speedometer Empty Re: Other speedometer Fri Nov 05, 2021 9:41 am

ouafnico

ouafnico
active member
active member
robmack wrote:I wrote a manual for this family of gauges that might help.

- standalone black to BATT ! (WTF, why a black cable to 12V positive)
Because the gauge needs two sources of power, one switched and the other unstitched.  So there ends up being three wires for power.  Why black?  Maybe the manufacturer ran out of colours.

Thank you. I'm checking your manual.

So I need to find the second wire for power ; but how I know what source must be switched and unstitched?

    

4Back to top Go down   Other speedometer Empty Re: Other speedometer Fri Nov 05, 2021 9:54 am

robmack

robmack
Life time member
Life time member
All power comes from the BEP 3.0.  Those connections would be BAT for unswitched, SWP for switched and GND terminals.

To get RPM to show on your gauge, you have to build an integrator circuit that connects between the BEP RPM output and the TACH input on your gauge.  http://www.motobrick.com/index.php?topic=11148.msg96957#msg96957



Last edited by robmack on Fri Nov 05, 2021 11:24 pm; edited 1 time in total


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

5Back to top Go down   Other speedometer Empty Re: Other speedometer Fri Nov 05, 2021 10:21 am

ouafnico

ouafnico
active member
active member
robmack wrote:All power comes from the BEP 3.0.  Those connections would be BAT for unswitched, SWP for switched and GND terminals.

To get RPM to show on your gauge, you have to build an integrator circuit that connects between the BEP RPM output and the TACH input on your gauge.  http://www.motobrick.com/index.php?topic=11148.msg109084#msg109084

Yep, just need to find on the gauge what wire need to be unswitched, if I consider the actual black is the switched one.

I didn't know I will need a new circuit for the RPM  Crying or Very sad

    

6Back to top Go down   Other speedometer Empty Re: Other speedometer Fri Nov 05, 2021 5:56 pm

robmack

robmack
Life time member
Life time member
It's a peculiarity of this family of gauges.  Normal gauges don't need the circuit.  The reason is outlined in the Motobrick page I linked to.


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

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