The Lost Boys (1987) on Netflix

Financial troubles force a recent divorcée and her teenage sons Mike and Sam to settle down with her father in the California town of Santa Carla. The town is plagued by bikers and some mysterious deaths. At first, Sam laughs off rumors he hears about vampires who inhabit the small town, until he makes friends with two other boys who claim to be vampire hunters. But after Mike meets a beautiful girl at the local amusement park, he begins to exhibit the classic signs of vampirism, sleeping days and staying out all night, and is drawn into the gang of bikers by the beautiful girl. The younger boy starts getting into trouble because of his friends' obsession. Fearing for his own safety, Sam recruits the two young vampire hunters to save his brother by finding and destroying the head vampire.