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Darryl.Richman
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VBMWMO #6285
Surf City, USA (Santa Cruz, CA)
Joined: 10/27/2006
Posts: 2185

My R52 had problem a few weeks ago; the nut came off the front of the magneto shaft and jammed in between the magneto gear (made of novotex) and the cam gear. This broke the magneto gear; it also broke the idler gear between the cam and crank gears (also made from novotex). Fortunately, neither the cam nor crank gears were damaged.

I've just received replacement magneto and idler gears, so I was working on the project. When I got the magneto gear mounted, I discovered that the magneto didn't turn over smoothly; it would occasionally jam...

So, I took the magneto apart and found that:

a) the small gear that's pinned on the nose of the generator shaft was cracked and missing a tooth;
Cool the pin that once held the small gear on the generator shaft is sheared off;
c) the medium sized gear that runs between the magneto and generator shafts is nearly worn out; and
d) that gear is also rather loose on its bushing.

Naturally, now that I want to investigate more closely and see a parts list, the D2B magneto site (http://geschichte.cjb.cc/d2b/) I carefully bookmarked seems to be down. Has it moved or is there a back up site?

Is there a source for these parts? I'm thinking I need at least the small and medium sized gears and the pin, but possibly also the bushing. Preferably in the US, but I am resigned to another wait for parts from across the Atlantic.

Thanks very much!

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Darryl.Richman
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VBMWMO #6285
Surf City, USA (Santa Cruz, CA)
Joined: 10/27/2006
Posts: 2185
Need D2B magneto parts

The magneto site has moved:
http://histor.ws/dmag/index.htm

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EuroIron
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Joined: 04/23/2007
Posts: 414
Need D2B magneto parts

would it be possible for you to post pix, dimensions as well, of what you seek?

I may be walking over it and not know.

But a simple bushing I would think would be no problem and typically isn't in my world, but I do have a reasonably equipped machine shop.

Darryl.Richman
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VBMWMO #6285
Surf City, USA (Santa Cruz, CA)
Joined: 10/27/2006
Posts: 2185
Need D2B magneto parts

I just took some photos. I may have a line on the original pieces, which would be better for me because I'm a shadetree mechanic and don't have access to a lathe.

Here are all the pieces:

The bigger gear is badly worn and is very loose on the bushing. The bushing is supposed to have an OD of 13.7mm and the gear, an ID of 14mm. Mine are 13.4 and 14.2, respectively. You can see all of this here:

What you can't see there is that this gear has a bite out of one tooth. I think that may have happened when the locking pin (first picture, upper left) broke into two pieces and one half ended up falling out and to the bottom of the magneto case.

The smaller gear is broken, and a tooth came completely free of it:

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Peter D. Nettesheim
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VBMWMO #5744
Joined: 01/27/2006
Posts: 128
Need D2B magneto parts

D,
All the parts you seek are readily available. They can be had from A&W Osterhaus, Iserlohn. Phone #0114923714825. Speak with Andreas. What you didn't mention is what gear size set you need. Did you know there is more than one? The difference in gear sets changes the speed of the Magneto commutator in relation to the generator speed. Replace the bearings on the rotor also. There is a special insulation washer that goes behind the outer race to isolate it from the housing. I'm sure you don't have that and you will need it if you are replacing the bearing. There is also a trick to reinstalling the bearing cover but that is for later.
Osterhaus normally send things in a few days. When you find someone in this country that has parts and knows anything about this specific magneto, let me know. I don't think he exists.
Peter D. Nettesheim

Peter D. Nettesheim
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VBMWMO #5744
Joined: 01/27/2006
Posts: 128
Need D2B magneto parts

D,
One more thing...
The reason for the failure is improper lubrication to the front bearing set via the wicking cord which is done through the two spring caps at the top of the magneto. You do oil them prior to each time you ride as recommended in the manual, don't you???
Please don't ask me the same question............
Peter

Darryl.Richman
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VBMWMO #6285
Surf City, USA (Santa Cruz, CA)
Joined: 10/27/2006
Posts: 2185
Need D2B magneto parts

Peter, an hour before you posted I placed an order with MZ-B for the various parts. They seem to have everything. I did have to go count teeth on the generator gear, there are 12 and 13 tooth versions (mine has 12).

Actually, the reason for the failure is that the motor stopped very suddenly, when a nut jammed between the magneto and cam gears.

But you're right about the apparent lack of lubrication to the intermediate gear, which is badly worn. However, if you look at the photos, which I took as I removed items from the case, you can see that all these parts glisten with oil, and I had filled the oiler when I got the bike here in the US, which was about 300 miles ago.

I do know that there's a guy named Johnny Eagles in Orange County, CA, who can repair these magnetos. He owns a number of bikes from the teens and 20s, though none that I saw are even German, let alone BMW, and specializes in magneto repairs. I know someone who was very pleased with the work he did on a D2B for an R12. He's a member of the AMCA, and I think he may advertise in their magazine.

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Darbone7260
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VBMWMO #7260
always sunny Tucson, Arizona
Joined: 03/22/2007
Posts: 11
Need D2B magneto parts

from the AMCA membership roster

John Eagles- member # 16
2584 E Delia Lane
Orange, CA 92669

(714) 538-0416

Best regards

Larry

Barry Robin
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VBMWMO #52
San Francisco, Ca.
Joined: 10/27/2006
Posts: 204
Need D2B magneto parts

ok darryl- i've got the magneto repair place for you. here it is:

Savage Magneto Service
2415 Radley Ct # 7
Hayward, CA 94545
Phone: (510) 782-7081

they rebuilt mine and it's great-top notch work. more importantly, all these guys do is build and repair mags, generators and engines from antique airplanes; that's right, they do old biplanes and things like that. going into there place is quite the time warp. odds and ends on display all over. and ever wanted to buy something like a working rotory pratt and whitney engine from 1932? they have one sitting in the middle of the shop.
oh-and they can do things by mail too...

-barry

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