Forum bmwbike.com

3 cnrank-shafts broken on 2000Km.
Last broken at the conus of the fligtweel.
Who knowes about that??

I have heard of only one crankshaft that broke, and it broke at the cone of the generator. It was an R69S, that had been used for a year with no vibration damper.

To get a good answer about why you have broken three crankshafts in 2000 km, more information is needed. You probably have a long story about how each crankshaft broke, how the engine was being used at the time, the location of the breaks, what parts were replaced, and who did the work. It would help if you could describe all this.

I totally agree with Allan - a broken crank is a very rare occurance - but three in 2000Km sounds almost impossible!

The only time I have replaced a broken crank was on a 1955 R50 that had parted right across the rear web - not so serious that the engine failed to run. In fact the owner rode it to my workshop complaining of a noisy engine!

But yes, more information please.