Hey guys

I've been looking for a NSR250 for a while. I've found that seems to be in decent condition but it's on the other side of the country (and I'm in South Africa). I've been grilling the owner with Qs as I can't just go over to see the bike in person.

He's told me - the battery is not charging. Could this be a bad regulator? I've had this problem on a few of my bikes before.

He's been running premix, but only because the previous owner said that he didn't have faith in the oil pump. He says he's been running 20:1. This sounds like way too much oil in the mix, and says that there's a bit of black oil leaking out the pipes. What do you guys think?

He also says that he doesn't know if the powervalve is working or not (I'm not sure he even knows what that is), what sort of question could I ask him to ascertain whether the powervalve is fully functional.

Thanks!