A friend of mine has one, now 360.000 kms (!), one of the first models.
Still the same pistons etc! (changed rings-yes)
Porsche designed shaft drive.
He found the choke mix too lean to start properly in winter; needless to say he thinks it is a very reliable bike!
The frame can break at critical points.

if the engine is not properly fitted. Clattering primary drive (Like old Hondas) -expensive chain.
Stable roadholding, not a very powerful bike though, as fast as a good r 65. (his bike-my r65

)
wiemer