Black Head Question

Begonnen von Donovan, 14 Mai 2014, 15:07:16

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Donovan

Can anyone shed some light on the black head R25 bikes?

I read online that this was an attempt to help with overheating and only issued on the R25/3 but paint was supplied for earlier bikes if desired. Initially I read a lot of this information here: http://forum.bmwbike.com/read.php?10,3981

I have been told by more than a few BMW experten that this is a myth and BMW *never* under any circumstances ever painted any heads black and I was more than a little incorrect to think otherwise.

I have seen pictures online that would seem to confirm this practice, but they are old black and white pics and I suppose shadows or other issues with the pics could be making the head appear black.

Many of you on this forum have advised I paint my head black.

So does any definitive factory information concerning this practice exist? A service bulletin or something like that? I have not been able to locate anything like this on my own. I tend to believe BMW did in fact paint the cylinder, head, and valve covers on the R25/3 black but I sure would like to be able to prove it. BTW -- my own bike has remnants of paint on the head but I cannot say who put it there originally.

Cheers,
Donovan

Donovan



rolf.soler

Of course they were painted black ! by BMW ! exactly as you say, in the 25/3, and recommended in restrospect for the 25/2
see here:
or here: http://cms.bmw-einzylinder.de/index.php/baureihe/kurzuebersicht-ueber-die-bmw-modelle-r25-bis-r25-3.html
or here: http://www.bmw-einzylinder.de/Vergleichstabelle/default.html
there is an official BMW-Memo somewhere (I've seen it), I'm sure somebody can send you a link

Kurt in S.A.

Someone in the US that seems to be knowledgeable of the singles is Jack Wells.  He's part of the vintage group at each MOA rally and usually provides a talk on what he knows about them.  I think he has one of every kind.  I contacted him when I was looking for leads on where to buy one for myself.

Another good person in the US is Richard Sheckler.  Of course, Vech is a great resource.  But Jack would be the first person I would check with.

Kurt
Kurt in S.A.

rolf.soler

here it is from the horses mouth; simply in the BMW repair manual for 25, 25/2, 25/3:

page 75 - 78 (changes during series), and explained why

Donovan

Zitat von: Kurt in S.A. am 14 Mai 2014, 16:21:04
Someone in the US that seems to be knowledgeable of the singles is Jack Wells.  He's part of the vintage group at each MOA rally and usually provides a talk on what he knows about them.  I think he has one of every kind.  I contacted him when I was looking for leads on where to buy one for myself.

Another good person in the US is Richard Sheckler.  Of course, Vech is a great resource.  But Jack would be the first person I would check with.

Kurt

Kurt,

Funny thing is Benchmark is one of the places that I called about fixing the threads on my head and returning it to me black. They said they'd fix the head no worries but also informed me they were never black to begin with and they would return it bead blasted and silver only.

It is one of the reasons I posted this question.

Thanks,
Donovan

cledrera

But there ist a little light in the black head  ;D

No, not the spark plug.  8)
I mean the alloy gasket between zylinderhead and the valve covers.
Du bist im Recht; nun sieh zu, wie du da wieder heraus kommst. (v. Chamisso)
Lieber Einzylinder als zwei Fallschirme (v. mir)

rolf

In opposite to the "experts":
beginning to make all (!) Heads black were all 25/2s starting at Fin number 263 051 (and every 25/2 and 25 coming to the inspection or repair, should be blackened by the mechanics.....with the name of the color they had to use, Bulletin: engine, 2.52 from 09.09.52....including black valve covers (and other details....5° ignition, alloy gasket for the covers etc.)...., afterwards all (!!) 25/3 has black heads (called "Mohrenkopf"....but remember...starting with the 25/2s).....with the beginning of  R26 production  the head and covers was getting again Alloy color (because of the greater surface of the fins).
Definitively enough?
Rolf

rolf.soler

right, it started in the 25/2 ± after half of the production, with recommendations for mechanics to paint all the earlier ones anytime they came in

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