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R90/6 electrical question

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srankin
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Re: R90/6 electrical question

Post by srankin »

I am not sure about Snowbum's attitude on answering questions, he has a long article regarding funding for his site and how advertising and donations support it. There is a line;
BUT, PLEASE DO NOT CONTACT ME DIRECTLY ABOUT YOUR TECHNICAL PROBLEMS.

PLEASE direct your personal technical inquiries to the Airheads List, where questions and answers benefit more than just you.

So, I don't know if this is what he would consider a technical problem or not? I do know lately Tom Cutter has started asking for donations via PayPal to answer questions.
I know Tom will answer with a small donation, most likely Snowbum will as well.

So the bike is not running yet, Do you have any circuits completed that work? Like I have said, there may just be a chance now this particular wire is redundant to needs. Have you had any luck finding another wiring diagram? The best I have found are from EME, they not only show color, but pin codes as well. If you turn the key and nothing happens then I guess the loose wire should be hooked up to something, if you turn on the lights, turn signals, brake lights and nothing works again the wire may go to something. If all these things work, then it may not be needed. I would insulate it so it does not make contact because as a black wire it is not a ground wire.

I know I am being a bit obsessive and perhaps a pain. I would like to see the problem solved. I am frustrated my friend is on vacation from his shop this week and I can't just stop in and look at his collection of schematics and perhaps into a shell. St.
Owner of a 84, R80RT and 78, R100RS

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schrader7032
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Re: R90/6 electrical question

Post by schrader7032 »

I've never heard that about Snowbum. He may be slow to answer an email especially if he's never heard of you before. At a minimum he will require some exchange to verify who you are. So it doesn't hurt to try. I would agree that he likes for questions to come through various forums, so everyone can benefit from his responses.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

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srankin
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Re: R90/6 electrical question

Post by srankin »

I found a Hayes book with color schematics in it. Give me a bit to see if I can post the picture I took of them. I may have an answer. St.
Owner of a 84, R80RT and 78, R100RS

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srankin
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Re: R90/6 electrical question

Post by srankin »

Let me see if I can confuse everyone a lot with my pictures. Sorry, they are not as sharp as I would have liked.
In the first schematic a black wire comes off the condenser to the points to the coil
Black wire off of condenser to points to coils
Black wire off of condenser to points to coils
Maybe unrelated but another black wire is possibly for the horn/horns?
Possible  horn
Possible horn
The first mention of pin 50 is a black wire on the pin 50 for the starter motor solenoid going to pin 87 on the starter relay
pin 50 to 87
pin 50 to 87
Now it gets confusing in the other instances of black wires. I see a black wire coming off of pin 30 on the starer solenoid Going to an H pin on the circuit board, which has a black wire coming off of it going to the headlight flasher and horn switch the H pin
Pin 30 forward to circuit board.
Pin 30 forward to circuit board.
black from circuit board to h lamp flasher switch
black from circuit board to h lamp flasher switch
black wire from pin 87 starter relay to front
black wire from pin 87 starter relay to front
To head light relay pin 85
To head light relay pin 85
A black wire goes to pin 85 in the headlight flasher.

Yes, I am confused, I will look at things again to confirm things. St.
Owner of a 84, R80RT and 78, R100RS

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srankin
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Re: R90/6 electrical question

Post by srankin »

So normally I go to the Clymer book for schematics if I don't have an EME one handy. In this case perhaps I should have gone to the Haynes book first.
in their schematic there is a black wire listed for US only starting at pin 87 on the starter relay going to pin 85 on the headlight relay.

This makes sense as your mystery wire is inside the headlight shell and outside near the coils and starter relay.
Black wire pin 87 starter relay to pin 85 light relay
Black wire pin 87 starter relay to pin 85 light relay
Owner of a 84, R80RT and 78, R100RS

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srankin
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Re: R90/6 electrical question

Post by srankin »

I don't see this black wire routing or anything in the Cylmer book's schematic.

It will be interesting to see what the EME schematics show me next week when my friend is back in his shop.
Forgive the confusion and such, hope this helps a bit. St.
Owner of a 84, R80RT and 78, R100RS

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cbclemmens
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Re: R90/6 electrical question

Post by cbclemmens »

My Haynes manual wiring diagram shows a black wire running form terminal 87 on the starter relay to terminal 85 on the light relay and it marks this wire as "US only"

Craig

I tried to attach a photo - hope it goes through
Attachments
IMG_4030.JPG

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cbclemmens
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Re: R90/6 electrical question

Post by cbclemmens »

And you already had that.

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sblaylock
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Re: R90/6 electrical question

Post by sblaylock »

I have two wiring diagrams for the /6 - the 74 and the 75/76. The 74 does not have the wire going from 87a to the headlight bucket as is shown on the 75/76 diagram. As to where that connects, which was the original question, I too can't say as my R90S is a 74 and the R90/6 currently in my shop is also a 74 - both have the /5 switch gear.

As has been stated before, 50 does not connect to the board in the bucket. I called another /6 friend and he too has a 74.

74
20220506_115450.jpg
75/76
20220506_115613.jpg
Not to push you off this site but advrider has a dedicated Airhead forum where you may get someone who knows where 50 connects or will look in their 75/76 headlight buck for the answer.

https://www.advrider.com/f/forums/airheads.85/

Scott.
Scott Blaylock
Stoney Peak BMW Service
Victoria, BC. Canada
BMW Classic and Vintage Motorcycle Service and Restoration
service@stoneypeak.com

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srankin
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Re: R90/6 electrical question

Post by srankin »

Scott, the color schematic you have posted for the 75,76 bikes is the same pattern as the schematic Webmore posted at the very beginning of this thread, his was in B&W yours is in color.

Did you look at the schematic I posted where a black wire is clearly shown going from 87 on the starter relay to 85 on the light relay? It is marked US only?

I guess the deciding factor will be made when someone with a /6 opens up their headlight shell and looks for black wires and confirms where they are plugged into or not. Or even if there is a black wire going into the headlight shell.

I know I posted many other locations for black wires according to the Haynes schematics and it may be confusing but given the data posted regarding Snowbum's information and other things. The use of black wires by BMW is limited to only the items I posted pictures of. St.
Owner of a 84, R80RT and 78, R100RS

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