How goes it? Writing here from the island of Guernsey, in the Bay of St Malo just off northwestern France.  A while back I bought myself a beautiful pristine K75S bike that was taken care of wonderfully in its original condition by an elderly enthusiast that had grown too old to ride. I absolutely loved it. Smooth as you like.

So now my youngest kid at 17 is into motorbikes and through a cock-up with the insurance broker managed to get him insured on the bike for an absolute steal. However it means I needed a new ride so when a 1983 original run K100 came up for sale locally I snapped it up.  Friends it was less lovingly looked after, though only in recent years as the old chap I acquired it from has had poor health. Finding that it needs a lot done before I'll be able to comfortably ride it regularly on longer distances,  and so I found myself here as I tried to muddle my way around other peoples knowledge to make up for my lack of.

Job one I think will be getting an oil leak fixed, followed by a raft of other things needed for preservation, repair and comfort.  Anyone with help or tips for the first off the line model would be most appreciated.

Hello TJ, There is tons of information here, the folks are willing to help. 
Good luck with the resto.

hello TJ

Welcome!  Where is the oil escaping from?  There are a couple of common spots, some of which are relatively easy to fix, and some that are a little more involved.

Honestly haven't had time to check properly yet as recently bought. Need to get it indoors and cleaned up so I can have a proper look, but its getting a once over at the mechanics in 3 weeks so might just leave that to then and focus on the bits that are more in my comfort zone to be honest. The seat lock is broken, as are mirrors, frame needs some protective care in places and the original little slipstream deflector (hard to source) seems very yellowed and scratched.

Welcome TJ