Gen1s are pretty bulletproof, they can suffer with corrosion so check the condition of the exhaust studs, Exup cover bolts etc to get an overall feel for how many winter miles the bike has covered and how well it's been looked after. The OEM rear shock isn't really fit for purpose so see if you can find a bike with a replacement already fitted or factor in the cost of getting it sorted.
My top tip is to plead ignorance and ask the seller to show you where the Exup valve is on the bike and ask whether it ever needs to be serviced. This a pretty important piece of regular maintenance that would not be neglected by a knowledgeable owner, and if they go to the trouble of regularly servicing the Exup then that would be a good indication that the rest of the bike has been well looked after. If they don't do their own servicing and the bike comes with good service history then ask if they would mind if you checked that you could undo the bolts holding the cover on. Unfortunately even reputable mechanics / workshops will neglect to service the Exup so it is still worth checking that the bolts are not rotted in place and if they are then walk away or be prepared to spend out on getting this sorted. If you need to brush up on the Exup valve Pat's site is invaluable for this and more - http://www.cartestsoftware.com/fz1/exupmaintenance.html.
There are some well looked after bikes out there so don't just get the first one you see if it doesn't tick all the right boxes.
My top tip is to plead ignorance and ask the seller to show you where the Exup valve is on the bike and ask whether it ever needs to be serviced. This a pretty important piece of regular maintenance that would not be neglected by a knowledgeable owner, and if they go to the trouble of regularly servicing the Exup then that would be a good indication that the rest of the bike has been well looked after. If they don't do their own servicing and the bike comes with good service history then ask if they would mind if you checked that you could undo the bolts holding the cover on. Unfortunately even reputable mechanics / workshops will neglect to service the Exup so it is still worth checking that the bolts are not rotted in place and if they are then walk away or be prepared to spend out on getting this sorted. If you need to brush up on the Exup valve Pat's site is invaluable for this and more - http://www.cartestsoftware.com/fz1/exupmaintenance.html.
There are some well looked after bikes out there so don't just get the first one you see if it doesn't tick all the right boxes.