The K100 swingarm/ driveshaft runs dry, yes? How are the splines on either end get lubrication?

You remove the final drive, etc and manually grease the shaft splines.  

Plenty of arguement discussion on what grease type is best depending on what is available in your location.

I guess it should have been obvious. So how often do you pull your final drive and lube the splines?

A general rule of thumb is every couple of years or 20K miles/kms.  They can go a lot longer before wearing out.  

Removing the mudflap, rear wheel, etc is a fairly straightforward job.  Less grease is better than too much, otherwise you make a mess.

Thanks for the info.