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1961peter
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The parts book lists part 2866 as flexible metal tubing to protect the wiring running to the rear light.
Can anyone describe where this metal tubing starts.
Does it run from the battery to the tail light?
Does this travel along the mudguard or is it fixed to the mudguard stays?

Does anyone have a photo of the bracket that is fixed to the mudguard that the JM3 light bolts to?

I haven't found any suitable photos on the web.

Regards,

Peter.

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Peter Barnett

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
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Bosch JM3 Tail Light

Peter -

Curious...what year and model bike? There might be something in the BMW archives...

Kurt in S.A.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

Darryl.Richman
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Surf City, USA (Santa Cruz, CA)
Joined: 10/27/2006
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Bosch JM3 Tail Light

Peter, what bike are you working on?

I have a 1928 R52. I, too, have hunted for photos that show a period bike with the taillight, especially a Bosch JN3 taillight, mounted on the bike, and with the wire routing visible. I have had little luck.

Even the BMW archives have not been of any help; most of the photos there were airbrushed to eliminiate the distracting wires, and there's some other kind of taillight that I cannot make out in a couple of the photos. (May have been a prototype?)

However, I recently received a book BMW Fotoalbum 1923-1969, published by Johann Kleine Vennekate Verlag (ISBN 978-3-935517-29-4, published 4/07 in Germany; no author that I can find) that has many period photos that show bikes in use, some with interesting accessories.

There are several photos showing the JN3 mounted on R42/47 and R52/57/62/63 bikes. The most common arrangment uses a small bracket bolted between the rear mount of the parcel rack and the fender, and extending the JN3 far out into space above the rear fender. A couple pictures show the JN3 mounted to the top of a rear facing license plate holder. There are at least two other kinds of taillights shown the photos, and many bikes that have a headlight seem not to have a taillight.

The wire -- note, singular -- ran on the outside of the rear fender, on top, under the parcel rack. Grounding was achieved through the metal of the fender itself.

There is one picture in this book of an R42 that shows distinctly a flexible metal conduit running over the rear fender from taillight to someplace under the seat. There are other photos that show a plain wire in this position.

Although the photos are good sized, I cannot make out any kind of actual mounting hardware for the wire. It seems to be run, sometimes with a fair amount of slack, along the top of the fender. Not very neat and tidy. There must have been several clips up there to hold it in place...

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Bruce Frey
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Texas Hill Country, USA
Joined: 10/27/2006
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Bosch JM3 Tail Light

Bosch is a better source than BMW for these items because Bosch furnished items to BMW who just attached them.

I have a scan of a Bosch Manual in English (and German, too) for the D2A Mag which also gives info about the JN3.

The JN3 was typically used as a combination handlantern and rear light so it was demountable from its bracket and there was a single conductor inside a flexible metal tube (for protection and ground).

I have a readable pdf that is small enough to e-mail.

The Bosch Archives is quite helpful with things like this. I also have a good bit of Bosch data, so feel free to ask about it.

Ciao,

Bruce

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
Posts: 6844
Bosch JM3 Tail Light

Bruce -

Do you have a website that provides some of these details? On the VBMWMO webpage, we have something about the Bosch magnetos from in the early years. It might be good to include other resources as well.

Thanks...Kurt in S.A.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

1961peter
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Bosch JM3 Tail Light

Darryl, Bruce and Kurt,

Thank you for the replies.
The bike I am working on is an R62

Bruce, I would be interested in the Bosch pdf you have.
Can you email it to barnettfamily@paradise.net.nz or provide a web address for the Bosch archive?

Darryl, like you, I have found photos with headlights only, and with the light mounted on the rear number plate as well as mounted on the either the mudguard or carrier (The photo is not clear enough to determine which)
I will look at what Bruce can provide but would be interested in a scan of the photo showing the small bracket that fits between the carrier and mudguard.
I assume this is part 2876 but I cannot determine from the parts book what this looks like.

Regards,

Peter.

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Peter Barnett

Bruce Frey
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VBMWMO #6316
Texas Hill Country, USA
Joined: 10/27/2006
Posts: 574
Bosch JM3 Tail Light

Here is the Bosch Archive URL

http://www.automotive-tradition.de/en/wissen/recherche.htm

It is a bit like the BMW Archive site in that you have to do some exploring to find what you want.

The fellow I have talked to is Dieter Schmitt. Dieter.Schmitt2@de.bosch.com

With respect to the "DMAG" link on the VBMWO site, there is a lot of good information there, but look at it as you would Wikipedia.

Ciao,

Bruce

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