R50 rebuild

Begonnen von guest605, 23 April 2010, 08:51:50

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I own what I thought was a R69S. However, it appeared that it had no matching numbers. Furthermore it appeared that the engine mumber was 556850, which indicates that it is a R50 engine! The valve covers have two cooling ribbs but a small investigation made it clear that they were those of a R50S - clearly made to fool the viewer! Also, the carburetter type (1/24/45 - 46) makes it clear that it certainly is a R50.
Now, my question is: Is it possible - and how much would it take - to rebuild the engine into a true R50S?
It looks - from viewing at the specs - that the diference is Compression ratio 6.8:1 against 9.5:1 and carburettor type.
Still, the extra 9 HP would be nice.


Nice...yes....but not for long....it has a reason while only a few 50S was built (and engines now rare ;D)
Nevertheless....only number and covers an Carburettors doesn't make it sure that it was "only" a R50 (otherwise I think it too)..if you put these parts on a 69S...it runs also and it was a 69S inspite


Thanks Rolf,
However, I measured the width over the cylinders and it is quite clear that there is ca. 17 mm missing. Also, the cylinders are wrong (extra bolt missing and wrong shape).  Do you really think it is possible (or a chance of) to fit 69s stuff (cylinders, pistons and carbs), meaning a 69S could be build on af 50 engine block?



Yes...it's possible...but I suspect it is the same machine as we saw when we are at Egeskov? isn't it??
That was an R50 Engine!

You can do nearly everything with BMW's....wrong zylinders compares with wrong "Pleuels" (I don't know the english word at moment...conrods?)....and it runs....not perfect...but like an english cycle ;D


Yes, Rolf, it is that machine.

I have tried to dig into it's history but I couldn't go very far. It is certain that it has run as a police MC in the early seventies. It is possible that the 50 engine has been put into it by the police workshop but I'm not certain. At a later state this engine has been completely renovated and it appears that it has run for only a few 1000 km since then. In a way it would be a shame to begin altering it again (unles one could be sure it it would turn out as a true 69S) because it runs and starts perfectly. Compression is fine and it does not eat any oil whatsoever.
If you had not told me about the problem I could have lived happily with the pleasure of owning a rare machine. Furthermore, I am concerned about how to sell it when that time comes; how can I advertise it? as a R"59"S?
Or, I could tell myself that a R"59"S is even more rare than a R69S.
If I could fall over a good, renovated R69S engine I'd consider to make the change, providing the present engine "could be give a good home".



Oha ,
If I hasn't told you ...you may better sleep, perhaps....but so you earn money from the Seller ;D (if I remember well?)....and you know: more money-> better sleeping

But....do you really need 42PS?....or isn't 26 much enough?!....I would enjoy the Engine/Motorcycle...with his good running and his longlive engine (inspite of an S....69S or 50S...that is the same for short/er life.


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