Just bought this bike yesterday. I rode it, cut it off and re-started it, all the things you do before you hand over the cash. Everything checked out fine. Well, there are a few things to fix but nothing mechanically. Basically, the bike ran fine. But then when I tried to start it today, it just made a loud clunk!

Battery's good. All the electrical components work, lights are bright. There does seem a leak in the gas tank.

It did rain the whole way home, 3 hrs, while the bike was on the trailer. And then all night too, with the bike still on the trailer.

Read somewhere that maybe the battery has bad connections and so it can turn the starter over, not enough power.

What could cause this to happen overnight? Shouldn't be the rain, should it?

Doubt that the rain hurt anything

but describe this "There does seem a leak in the gas tank"

likely the battery won't hold charge over night