“My girlfriend dumped me, so I bought a motorcycle” is the title of the first chapter in “Motorcycle,” an offbeat low-budget slacker comedy in which the motorcycle in question is owned by a series of discontented 20-somethings.

Chris (Chris Pratt) is the spurned lover who buys the bike to soothe his damaged emotions. Sweet but slightly desperate, Chris hopes the motorcycle will give him a good excuse to hang out with girls. (“Want to go for a ride?”) At the very least, he wants to look cool when he runs into his ex-girlfriend.

Alas, the motorcycle is stolen and winds up in the hands of Ingrid (Paula Rester), a misanthropic bicycle messenger who’s trying yoga and affirmations to achieve happiness. She winds up giving the motorcycle to Brandi (Brandi Perkins), a mildly white-trash girl who works at a barbecue restaurant.

The three main characters, whose paths and stories overlap and occupy the same period of time, are bored, listless youth, each of them slightly uncool and prone to having quirky, low-key conversations, “Napoleon Dynamite”-style (or, if you prefer, “Clerks”-style). They are unambitious, and they live in an unnamed medium-sized city with no distinguishing features — Anytown, U.S.A., where the nation’s youth have nothing to do.

Writer/director Paul Gordon shot the film on grainy black-and-white, which suits the low energy of the slackers in the story. The characters are amusing, and the film is likable, but it’s not quite funny enough to sustain itself, even at the short running time of 81 minutes. There needs to be a little bit more of something — humor? depth? plot? — for it to feel complete.

That said, it’s not a bad film, and it has the makings of a potential cult classic. After all, everyone likes a movie about nothing every now and then.

B- (1 hr., 21 min.; Not Rated, probably R for a lot of harsh profanity.)