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Matteo
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Next year (2015) is the year for my R51 project. My question is whether the R51 headlamp is the same as the R12? At Oldtimer Garage website in Poland they show the same headlight for both. At the RRC Tuning website, they have two versions of the headlight for the R12, one with magneto ignition and one with Dynamo ignition. As far as I know, the R12 was only magneto.

Anyone know the scoop?

Thx
Matteo

Darryl.Richman
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VBMWMO #6285
Surf City, USA (Santa Cruz, CA)
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First off, I don't think the

First off, I don't think the R51 headlight is the same as the R12. I don't have a parts book for the R51, but the part number for the R5 is different than the R12.

The R12 had two different headlights, one for magneto ignition (service and Wehrmacht models) and one for battery/coil ignition (civilian models). The difference is that the battery/coil models have a red generator lens to the right of the key; both models have a bakelite plug to the left for the 8 amp fuse. (Actually, there are *four* headlights listed in the parts book; for each of the above, there is a corresponding one that accepts a drum speedometer instead of the usual pointer speedometer.)

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Bruce Frey
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Texas Hill Country, USA
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The basic Bosch EAS 170

The basic Bosch EAS 170 headlight was used on BMW R12-R71 as well as other makes and came in different versions depending on the speedometer, ignition type and RH or LH dipper and other differences like cable entrance holes. Headlights with similar shapes were used on autos, too.

The R12 (and R17) probably had more versions than the R5-R71 because it came it with either magneto or battery ignition, and with the early walzentachos and later zieger tachos. Having said that, I have a fair amount of period Bosch literature and it gives subtle differences in R5-R71 headlight model numbers for different models and different years even though they are basically the same. Unfortunately, it does not describe the differences although it may be a military spec issue. Headlight models for twin BMWs are all EAS170x2T(xxxx), with the suffix being different for different configurations.

I am not very conversant about R11 and R16, but one Bosch data sheet from 1943 shows the 1935-1937 (sic) R11 as having either an EAS170x2T5 or 2T8 headlight. The R12 has separate data shown for that period so I do not think it is a model number typo. I thought all R11s had tank mounted speedos and I have seen EAS170 headlight shells at Veterama with no speedo cutout, so it could be a variation of it was used on late R11.

I hope Santa/St. Nick was good to everyone!

Cheers,
Bruce

Bruce Frey
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Matteo, I really didn't

Matteo,

I really didn't answer your question, but the headlight offered by Leszek and RRC's battery version will work on the R51.

A caveat.......not all repops are the same and headlight parts may/may not freely interchange between originals and other repops. The same with distributor caps and rotors. If you but a new cap, get a matching rotor to go with it.

Bruce

Matteo
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Thanks

Thanks Bruce and Darryl. My bike is a bits bike. The engine case is unstamped and the frame is a true R51 as is most of the major parts. I'll keep looking for a headlamp and may go for the RRC's if I don't find a better alternative.

Matteo

Darryl.Richman
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Surf City, USA (Santa Cruz, CA)
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Since we have the first gen

Since we have the first gen plunger experts here... Wink Did these bikes come with a sidecar plug? My R51/3 has one, but I don't see one in the R5/R6 parts book.

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Bruce Frey
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Texas Hill Country, USA
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Sidecar plug

None of my parts books (R12/17, R5, R5/6, R51/71) show a plug/holder in either the regular parts or accessory sections.

The Bosch wiring diagrams show a separate fuse box (sicherungdose) going to the sidecar light, but there is no fuse box in their catalog that quite looks right for the job. The catalog does show the plug and holder (steck and steckdose) that I am used to seeing.

I expect it was available as an option from factory or dealer, but given the large number of sidecar machines, I would have thought it would be in the sidecar accessory list.

Bruce

R68
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sidecar plug...

The R5-R6 has a small triangular bracket with three electric terminals, and it attaches to the horn bracket. I've only seen a picture, and I'll send the pic if I can find it. It's not shown in the parts book; must be very rare? I don't know about the '38-'41 plungers, or R51/2.

Bruce Frey
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Ground collection terminal

I believe you are thinking of a ground collection terminal. Bosch shows them in their schematics as a place to land the ground wires from the battery, headlight and, depending on model, the ground lug on the generator. It is attached to the horn mounting bolt. A picture of one from the Bosch catalog is attached.

While all the Bosch schematics show this piece, I have never seen one fitted on a bike or for sale at Veterama.

Since this is grounded, it would only have provided a place to land a ground wire from a sidecar, not to connect the positive side.

Bruce

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Matteo
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I have 3 plunger frames, a

I have 3 plunger frames, a '54 R51/3 (March 3), a '52 R51/3 (April 25), and a 1938 (around or in the summer). Only the '54 has a sidecar plug. It is on the left side on the bike. If I remember correctly, the /2 were on the right. The plunger frame has the throughhole for the sidecar on the right side and would interfere with the sidecar plug if it was on the right.

Also the '54 has a mounting bracket for a rear brake switch.

avi
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israel
Joined: 01/08/2014
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plug conector fo sidecar

Can you please upload some photos of the frames?
As far as i know the bracket for side car is made on all plunger frames from R51/2.

VintageSalesand...
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VBMWMO #7368
Corona, CA
Joined: 03/24/2008
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Sidecar Socket

That is correct.

Jeff

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