Author Topic: No Speed Output from BEP 3.0  (Read 567 times)

Offline el_major

  • Curious
  • Posts: 4
No Speed Output from BEP 3.0
« on: April 13, 2019, 03:13:19 PM »
Hi guys,

Currently modernising my K1100LT (96) and working on replacing the old brotbox with an Acewell MD85-556

However, I've ran into a massive snag. my BEP 3.0 unit doesn't seem to be outputting a signal from the SPD pin.

The original brotbox works absolutely fine, so it's not a problem with sensors or wiring before the BEP box.

I have verified that there's no signal from the SPD pin with an oscillosope and there's no fluctuation in the output. and checked for continuity from the sensor through to the SPD output.

Almost every other function works correctly (including the RPM)
The speedo always displays N for neutral, even when in gear, however.

If anyone has any possible insight into what I could be doing wrong here, that would be amazing. Attached are how it's currently wired.
Thanks in advance.

  • Dorset, UK
  • K1100LT 1996

Offline johnny

  • TrailBrakingThrottleWhacker
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  • Posts: 6669
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Re: No Speed Output from BEP 3.0
« Reply #1 on: April 13, 2019, 03:17:26 PM »
greetings...

modernising... you mean you using modern isotorpes of molybendinum on the splines... or what... please explain...

j o
  • :johnny i parks my 96 eleven hundert rs motobrick in dodge county cheezconsin  :johnny

Offline Laitch

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Re: No Speed Output from BEP 3.0
« Reply #2 on: April 13, 2019, 04:18:26 PM »
modernising... you mean you using modern isotorpes . . .
Isotorpes are my favorite torpes. :Rabia:
  • Along the Ridley in Vermont.
  • 1995 K75T 72,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline Laitch

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Re: No Speed Output from BEP 3.0
« Reply #3 on: April 13, 2019, 04:34:14 PM »
If anyone has any possible insight into what I could be doing wrong here, that would be amazing. Attached are how it's currently wired.
What might be helpful is clear diagrams of the connections you have made instead of obliquely-angled photos of wiring, but the photos might ring some bells among those who have attempted this conversion.
  • Along the Ridley in Vermont.
  • 1995 K75T 72,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline rbm

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  • Posts: 1941
Re: No Speed Output from BEP 3.0
« Reply #4 on: April 13, 2019, 07:32:34 PM »
Laitch and Johnny are correct.  Pictures of your wiring don't help much without a corresponding schematic diagram with the lead colours clearly depicted.

Have you confirmed that the Brown wire from the speed sensor in the final drive has continuity to frame ground.  Normally this is achieved within the OEM gauge cluster itself.  The BEP 3.0 should also have that lead grounded at the input connector but it is a good idea to check.
1. Disconnect the speed sensor from the harness at the point under the right battery cover.
2. use a ohmmeter to check that the brown wire on the harness side of that connector has continuity to frame ground (the under tank grounding point or to the battery negative.

If there is no continuity, it's possible your lack of speed indication is a result of the sensor floating relative to ground and thus not supplying a signal to the BEP.
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline el_major

  • Curious
  • Posts: 4
Re: No Speed Output from BEP 3.0
« Reply #5 on: April 14, 2019, 11:18:56 AM »
Fair comments, I appreciate the help.

rbm, I'll check continuity in that way specifically when i'm next out there. I have a feeling I've checked, but will double check!

Here's how it's currently wired up using a combination of the Acewell wiring diagram and the BEP diagram. Also attached is the original wiring diagram for the acewell for reference.

Thanks guys!
  • Dorset, UK
  • K1100LT 1996

Offline el_major

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  • Posts: 4
Re: No Speed Output from BEP 3.0
« Reply #6 on: April 14, 2019, 12:39:10 PM »
Hi Johnny.

That's exactly what the above is.

I can trace it out on some paper with pencils if you would prefer?
  • Dorset, UK
  • K1100LT 1996

Offline rbm

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  • Posts: 1941
Re: No Speed Output from BEP 3.0
« Reply #7 on: April 14, 2019, 12:39:20 PM »
Just to verify an observation I have.  The Acewell gauge appears to have two black AMP connectors.  One cable set has a blue sheath and the other cable set has a black sheath.  It appears in your photos that those two sheathed cable assemblies terminate at the BEP 3.0.  Can we assume that those cable sets came with the Acewell and have exactly the same colour coding of the wires in them as is shown on your first attachment?
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline el_major

  • Curious
  • Posts: 4
Re: No Speed Output from BEP 3.0
« Reply #8 on: April 14, 2019, 01:14:17 PM »
Hi rbm, thanks for looking.

You are correct, yes. These are the extensions provided with the acewell and the colours line-up.

Thanks :)
  • Dorset, UK
  • K1100LT 1996

Offline nazdcm

  • Motobrick Curious
  • Posts: 12
Re: No Speed Output from BEP 3.0
« Reply #9 on: May 15, 2019, 05:04:52 PM »
Hey El Major, did you figure out your issue with the SPD pin?
I am also about to rewire my k75 with a BEP 3.0 and an Acewell MD085-553B
Did you not have any issues with the RPM and the square wave thing?
Also, did you try to to waterproof the BEP a little? Maybe wrap it in tape or something?
And i will gladly take any hints or advice you may have! :)
  • Edison NJ
  • 91 K75

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