Hi,
I'm a new owner of a 1956 R26 with no prior experience on BMW singles.

I have two questions please, and I would be most grateful for your assistance.
I am going to do a compression test. What pressure would an R26 engine in good condition read?

Mine is the version with the metal air filter. This strikes me as a bit "crude".
Is the filter reliable enough to maintain a clean carburettor?
Is there a benefit in upgrading to the filter in the later R27? If so, has anyone done this?

Thank you, Liam

Hi Liam,

Compression of a healthy R26 should be 7,5 ato (~110,2 psi).

In the '50 BMW's idea of an airfilter was rather simple. Just catching stones. A paper airfilter should be an improvement and BMW did it on the later R26's just like the R27. At the same time BMW also changed the carburettor on the versions with the paper airfilter. That does not mean that your carburetor would not work with a paper airfilter. Perhaps you have to change the nozzle too. The bodywork for changing to an airfilter is rather rare (and expensive).

Regards, Roelof Jan

Hi Roelf,
That's excellent information, thank you.
Now you know that one question leads to another!
I think I will go ahead and change the air filter to the later paper type, and I do accept that this will require
changes in the carburettor, but I am in the position where I am going to have to spend money on my existing
carburettor anyway because the threads on the carburettor body that receives the needle jet/main jet are damaged.

So my next questions, and again there are two!
My existing carburetor number is 1-26-55. I need to find out what is the number of the carburettor on the later
R26 with the paper filter. The number of the carburetor on the R27 is not relevant as I understand that this
has a higher horsepower engine.

Can anyone recommend a supplier of new, or reconditioned carburettors for these machines?

Thanks again,
Liam

Hi Liam,

Try Salis Parts at bmwclassicmotorcycles.com/. One of our advertisers.

Regards,

Wim van Heugten

Thank you Wim.