A few suggestions (I like "young turks", because it's no good hiding behind lists; a person's gotta choose)
angry young men
rumble fish (stolen from a OK film; I love the words though: rumble fish, mmm.)
jail bait (stolen from a much better film, but what the film was called, anyone? He (Farley Granger) is young and gets caught up with bank robbers, one of whom has only one eye, and is annoyed that newspaper reports always refer to thjis fact; she (Name?) is beautiful and the daughter of a con (?), and her mother (?) keeps calling him "jail bait". )
Outsiders (from another film, not really that good, but this isn't a film discussion, so I'll stop)
If anyone suggests "brat pack", they should be banned from internet use. What a horrible phrase.
And, as regards "punks", I would say you would have to say "young punks", otherwise it does sound like you're talking about Sex Pistols etc. fans, BUT "young punks" is something only old fogeys say.
And, they are Teddyboys, in the film, but rowdy young men are still called "Halbstarke" in Germany, although they bear no resemblance to those beautiful moped-riding gods of yesteryear.
But "Die Halbstarken"
And what a great film. Get out there and see it.
When the girl stands there and says "Er ist fertig". COOOL.