Kakashi is also very fast, with the sharingan he won't have problems keeping up and evading attacks. Let's not forget how Kakashi was dancing around Kakuzu's 3 hearts assaulting him while simultaneously avoiding Hidan and his scythe without getting touched. And we've seen Kakashi handle himself pretty easily against multiple V2 Jins so Killer Bee shouldn't be too bad a problem. If killer bee goes BM then he digs himself a grave because he'll get 1 shorted with kamui.
In the end I see no reason for Kakashi to not win.