I have got well over 70k on mine now, i had it back in 2008 with just 8k on it all i have ever done is the normal service, change chains and recently the clutch.....which gave me a load of grief which is on the forum, the only reason i ask is while sorting my clutch out i had to get a new pressure plate from a dealer and they told me that these were only designed to last around 60k.
With my recent knee op i was considering something with shaft drive but still love the ride i get drom this even though it is a constant battle with the rust round by the engine mounts.