Hi Nqman
Welcome to the forum !!!!
First off, what year bikes are you looking at ?
There are three 'generations' of the R65, the '78-'80 year the 'first generation', '81-85 the most number of bikes made , the '85-'87 monoshock bikes .
The first generation bikes had some parts that were specific to those years of production, harder to find nowadays .
The second generation has a lot of upgrades from the the first generation, parts are pretty easy to find .
The monoshock bikes share a lot of parts with the 800 and 1000 cc bikes made at the time, easier to get parts, they aren't R65 specific .
If the bike has been cared for and maintained you may not have much to do, but usually the bikes have been neglected and require a bit of work and parts replacement .
If you are in a coastal region, corrosion can become a problem with the electrical system connections, as well as the threaded fasteners, steel bolts in aluminum corrode quite readily in a salt air environment .
With the km range you're looking at, the engine most likely won't be an issue .
I would be more concerned about possible corrosion in the brake system, if it hasn't been bled/fluid replaced regularly .
Water contamination in the transmission, shaft and final drive, is fairly common due to water getting into the transmission at the speedometer drive cable .
The condition of the transmission input shaft splines where they go through the clutch plate, if not cleaned and lubed, very worn splines can strip and require the input shaft and clutch plate replacement ( pretty much a tranmission overhaul) .
I'm giving you worst case scenarios here, but it can get expensive if you happen to find them on your bike !!!!
Once you get the bike sorted out mechanically, if it needs it, the bike will run for years without too much attention afterwards .