Kotaro, An Audacious Karate Boy(1984)

Original title: コータローまかりとおる!

Lewd, long-haired karate kid Kotaro Shindo spends his days causing amok at the prestigious Tsurugamine Academy, until the Disciplinary Committee decides enough is enough, and puts a bounty on his luscious locks. Meanwhile other sinister forces are working in the shadows to put Kotaro to use for their own ends.