Go for Broke (1985)

"A quiet campus becomes a blood-drenched battlefield! Hell goes to school!"

At a Japanese school, a desperate student council struggles with a recurring problem. The aggressive and relentless members of the Yagyu biker gang stop by the school each semester to beat up the kids, steal their lunch money and vandalize their belongings. The kids want to fight back but realize they're too weak and undermanned against the bikers, and so they hire a handful of tough gals to train and defend them.