There's a movie from back in the 80's or 90's that I cannot remember the name. It was a karate/martial arts type movie. It had something to do with a guy teaching some kids how to defend themselves. They sang this song while they would fight, "bah-na-na-waaay, bah-na-na-waay, bah-na-nana". They would just sing that, reapeatedly. What movie is this from?

Karate Kid..

Hope this helps.

Not Karate kid... It's called Only the Strong (1993). Green Beret goes back to his hometown and teaches kids the martial art Capoeira, a style that uses music as the basis for its moves. Along the way he has a few run ins with the local drug dealer. Great action, awesome martial arts style! This is the movie you're looking for, Definitely!