Interspersed with dialogue from a cult-championed documentary about an ever-growing club of chopper-obsessed anti-heroes named the Sinners, the Choppertown soundtrack is peppered with some ferocious punk ‘n’ roll by bands in close acquaintance to various members of the underground motorcycle club. It opens with James Intveld trying to describe how over the past decade the club has evolved from a handful of guys who originally got together to drink beer and wrench bikes into a growing phenomenon. Southern California’s the Whitewalls delivers the first two songs with “Stay” and “Hell’s Kitchen”; the former a workable blend of punk-fueled rockabilly driven by some early Danzig-inspired vocals and the latter a punk driven gearhead anthem that sounds like a rootsy version of the Misfits. Infamous bike builder Jason Jessee gives a memorable spoken word bit before Santa Cruz’s Highway Murderers unleash their feral-sounding sludge metal with “Hammer” and the harder hitting “New Monia.”