R62 Project: The Beginning

[Darryl.Richman]

1) I don't have the magneto for the R62. But the R12 takes a D2B and the earlier bikes take a D2A. The difference is the direction the input shaft rotates, because the chain drive preserves the direction of the camshaft while the gear setup reverses it. The direction is indicated by the arrow stamped in the case

2) All of the postwar magneto bikes have a "wasted spark" system that fires both plugs on every crank revolution, even though the points are mounted on the end of the camshaft, because the points cam has two lobes. The difference in how they wear is what causes the frequently experienced differential timing on those bikes.

The magnetos on the split case motors fire only once every camshaft revolution (half crank speed) and a rotor inside the magneto with a small metal strip on the edge determines whether it will be the left or the right cylinder that fires.

3) I don't really know. But I would suppose you could put it in a vise and chuck up the input shaft in a drill motor, and then start probing with the VOM. I would suppose that one could follow the trouble shooting directions in the back of the 4-language /2 factory service book, since the regulator looks pretty similar.

[Peter D. Nettesheim]

D,
1)You are right on the money. The gear driven magneto is referred to as a "left turn" magneto while the chain driven is a "right turn". You can not interchange the two but a rebuilder can make a left into a right and vise versa if the buyer so requires. As you said the direction is stamped in the case on a removable plate.
On question 2 the number of revolutions is not really the issue. Let me pose the question this way: Why does the "D" zunder have that distributor strip? Why not just eliminate it and fire both plugs at the same time?. The magneto would be simpler to manufacture. The number of revolutions of the engine or cam does not change the fact that with that one set of points you could send a charge to both plugs at the same time.
The reason that the magneto only fires one side at a time with no wasted spark..........................the magneto is just not strong enough to reliably fire both plugs at once. Its four times the size of an R60 magneto but the older technology of this unit made it weaker than a modern unit. Simple.
Now to three..............
This is a bit difficult to explain over the keyboard. Like any analysis of a problem, the better you can isolate the indivdual components the easier it will be to determine the problem component. With the magneto on a bench, you can check the field, windings, brushes and other components by turning the generator into a motor. This is done by removing the regulator placing 6 volts pos to the pos brush and grounding the case (do not ground the other brush!). If the components are in good shape it will turn like a starter motor, just a lot slower. Then you need to look at the regulator which I have found to be a regular pain. Put the electronic one in and forget it.
Thanks for taking the time and when you run into that real bitchy problem.....drop me a note. Maybe I can help. When and if you want some more questions let me know too.
OK just one more..........and this is an important one to anyone rebuilding a R32 or R42 out there.
Tell me the difference in the transmission lubrication system between an R32/R42 transmission and a R52/ R62 transmission? Not knowing this screwed me up with a project for years...............
Peter D. Nettesheim

[Darryl.Richman]

Oh! Oh! Oh! Pick me! Pick me!

This little thing is mentioned in a by the way manner in Slabon and Knittel's Buyer's Guide, and it stuck in my head. The earlier transmissions were filled with grease rather than oil.

And the reason that stuck in my head is that when I took my R52 apart, I found that the final drive was grease filled. However, in my case, that was done because the final drive case was in such poor shape that it wouldn't hold oil any more. It was cracked and broken and had already been rewelded on both mounting flanges. Fortunately, both the ring and pinion gears and the "mitnehmerflansch" were all in good shape, and Dreher has new castings that work great -- and for the price, they should!

[Barry Robin]

sorry to butt in...

i'm quite enjoing this catechism question and answer thread-thanks to both of you; besides learning a lot of usefull information, it's nice to know that the factory did things a certain way that helps to put in context all the eye-opening internal oddities that i dealt with on the R11-so i'm not alone!

and i thought i'd throw in a tidbit on my R11 tranny: because my bike sat undisturbed for all those years in the garage, i found what i may assume is close to the original grease in the tranny case...yuck! semi-solid sludge that only loosend up with a blowtorch and a chisel...

sorry to interupt; we now return to our regularly scheduled program.

-barry robin

[Peter D. Nettesheim]

D, Who's this robin guy???? He sounds like he may know something. I'm going to have to reserve some of the tougher questions for him.
First, yes, you finally get the A+. The r32 and 42 transmissions were greese transmissions. Do you have any idea how hard it is to prevent thin oil from leaking out of a transmission that was designed to hold greese?
Next question:
Explain the use of blue and white in the BMW emblem.... and don't give me any of that propeller in the blue sky crap. No the white doesn't represent the clouds either. There is a very appropriate that the colors are blue and white. Why?
Peter D. Nettesheim
P.S. I would like to get some answers from someone else too. Come on, all chime in now!

[Peter D. Nettesheim]

D,
I have found that being of German decent and being enrolled in an engineering school for a few years may just somehow help me better understand the design of the BMW products. I don't quite fully understand it, but when I work on these bikes things just make sense. I once had to work on a french car and nothing made sense. It was not my lack of experience with the product its just that on everything I touched I found myself asking "why would you make it like this and why would you put it together like that?
So I have to once again open the can of worms and say that "a slinger is in no way a filter". Can you explain why? Can you bring forth a reasonable argument as to why this cannot possibly be a filter? Do you even agree? This statement does not change the fact that it collects debris and needs to be cleaned but I can confidently say that at this point , after years working with the early engines and seeing how the slinger in the later bikes came to be, that it is not a filter and that this device was never intended as a filter. To help my argument, I will at this time only say "what is the purpose of a filter and what does a good filter help to prevent?"
Anyone else have something to say? and please tell me you know exactly what the slinger is before you answer..........
P.Nettesheim

[Darryl.Richman]

D, Who's this robin guy???? He sounds like he may know something. I'm going to have to reserve some of the tougher questions for him.Good, because now that I've got my A+, I feel like I should quit while I'm ahead.

Next question:
Explain the use of blue and white in the BMW emblem.... and don't give me any of that propeller in the blue sky crap. No the white doesn't represent the clouds either. There is a very appropriate that the colors are blue and white. Why?

Rather than give another partial answer, I would point folks to the article on the subject that was in one of last year's editions of the BMW Mobile Tradition magazine. (I will have to hunt up the exact issue, but they're all available for free at the BMW MT site.) The basic answer is that the circular design came from the Karl Rapp logo (circle with a black knight chess piece) and the colors of the Bavarian wappen (heraldic shield) in a design that was close, but didn't actually infringe, upon the Bavarian state's design.

Here's one back at you, Peter: what are those Bavarian colors and wappen design supposed to represent? For extra credit, how do the Bavarians always refer to them?

[Darryl.Richman]

If you have some patience, you can hunt around the BMW AG web site and find the Mobile Tradition area. However, until they change the site again, you can use this link to it.

The article I was referring to is in the 2005 issue 1 of the BMW Mobile Tradition Live magazine. You can go to this page and download the pdf file. The article is titled "Fact and Fiction" on pages 38-41. The article begins:

The origin of the
BMW logo –
fact and fiction

There are two traditions concerning the significance of the BMW company logo and
trademark, offering two different interpretations of the blue and white fields in the
logo. One interpretation points to a link with a rotating propeller. The other relates to
Bavaria as the place where the products are manufactured. A closer look at the available
sources and the historical background reveals one account as a myth while the
other emerges as a historically plausible explanation.

[Peter D. Nettesheim]

Ok,
I guess you have more info on this one than me and I can't answer the one about how the bavarian's refer to the colors (blau mit weiss?)So we will leave it at that. Plus I'm the one who's suppose to be asking the questions anyway.................... Now I'm going to have to find a real bitch of a question to ask. Let see, humm.......how about the meaning of the "S" on the end of the original DM 175 T1S spark plugs for the R17....... How about what the "D" means on the same part?......
Peter D. Nettesheim

[Darryl.Richman]

Bavarians always refer to the "lozenge" flag, and Bavarian colors as weiss-blau, or weiss und blau -- that is to say, white-blue or white and blue. Never the other way around. (If you look at the Bavarian state web page, you'll see that they do follow this principle.

The white-blue is supposed to represent the sky in Bavaria. If you follow the link above, you'll find this line in the Bavarian anthem:

erhalte dir die Farben seines Himmels weiß und blau!
"Keep your heavens' colors of white and blue!"

So now you know!