Question about a 2002 Ninja 600

[Ethanol]

So I've never worked on anything this new but I got a titled one free (sorta) that I'm gonna clean up and flip. Problem is it's got a knock on the bottom end. Probably rod bearings. It rides ok, but it is noticable.

So

1) how much trouble is that to fix?

2) How long till it kills itself?

3) Should I just say "fuck it" and sell it super cheap as a "stunt" bike or something?

Thanks guys!

Also: We get our shop August first! I'm pumped.