I small update:
The seller turned out to be an experienced scammer and a pathological liar. What I naively thought was a bargain, turned out to be a dud and a money pit. The bike was probably sitting idle for years. I have spent $800 so far in repairs and problems are still cropping up every month. I hope the the big ones have been addressed. What remains: a rear suspension adjustment/replacement, oil leak fix, side stand, electrical gremlins, aesthetic upgrade, new tyres. I will probably need to spend another $700 in order to really trust this bike in longer trips.
Newest problem: the steering wheel is locked and can't be unlocked. The key is stuck on P, which means the headlights couldn't be turned off
and as a result the battery was drained overnight (any ideas on this one?).
On the positive side, I love driving it and I got accustomed to it very quickly.
But overall, a great disappointment. I don't know if I should give it away for the price I bought it or keep it and slowly fix things as they appear.
Oh no.. The one time I bought a 2-wheeler second hand also ended up a bit like that.
My tyres were 12 years old and hard rubber, gearbox did not shift properly, battery was weak.
Oh, I knew there was something else - the trip meter zeroing button (on mechanical odometer) had broken off.
Also, the small bulb which lights up the analogue instruments was gone so you did not get that reassuring glow in the dark.
All in all, I made a vow after that to never buy a 2-wheeler used again. Have never bought a new car in my life, and many used ones, so I don't apply that rule to 4 wheels. Still, my car needed all sorts of things replaced but I don't hold it against the car or the person who sold it to me.
Even with the bike I didn't hold it against the person who sold it to me. Well, maybe a bit. Oh, paperwork, such as manual and service book was absent. Did you at least get that? A book of instructions, and another book with stamps of oil changes etc?
If I was in your position I would either sell it again and buy a brand new one or keep it and iron out the remaining flaws. It is part and parcel of used vehicles that there is a bit of a list of surprises to be attended to after you first buy it. So if you sell it just to buy another second-hand one you may invite even more misery on yourself.
My last bike really made me miserable, especially when I almost had accidents and fell over once due to the gears refusing to change. That "key" problem with locked handlebars sounds miserable as does battery draining. You have to wiggle both the handle bars and the key but that is obvious, if that does not work I would not know.
I could never say "I love driving it" about that one I used to have, just the choke to start it, fuel valve and reserve seemed like a quaint idea when I got it but were too stressful for a beginner. Then those little things like the trip meter not zeroing and the instrument light not working further ruined the "love" factor. I did not like the riding position either after a while but does not sound like you have that issue. Maybe if you really feel bad about the individual who sold it to you it may be a sign though.