Obito forcefully took the juubis powers. I believe very soon we are going to see minato give naruto the other half of the chalkra.
After this happens it still wont be enough and heres what I think will happen....
Naruto has the chalkra from the tailed beasts from when he got swallowed he just doesnt know it yet. When he bumped fists with all of them they gave him everything they possibly could. This is why the 10 tails isn't in its perfect form. Naruto with the help of kurama will gather power from all of the tailed beasts WILLINGLY. And that is how he will be able to beat them.
just for the dude who posted. sasuke will get his face kicked in and we will see the whole vegita goku buu story all over again. naruto will be gathering this power and it will take awhile and sasuke will have gotten raped and karin will heal him and he will buy naruto time to charge up his spirit bomb.