A PG RATING five years ago meant a couple of swear words (but not fuck), a first love (but no sex), and a small brawl (with some blood spilled, but no guts). These days, PGs are about teenagers who do what adults do in Rs, but not on screen. So we get heavy titillation instead of heavy sex, and scuffles suggesting murders instead of up-front violence.

Peter Yates' PG Breaking Away returns to the old formula. Against a tide of cinematic drivel, Yates and a few other directors are making a stand with small-scale movies which make up in honesty for what they lack in monumentality and pyrotechnics. Cheered on by his audiences and lauded by critics, Yates, with a movie about bicycles, has out-distanced power-driven, Dolbyized, super-slick monsters like Rocky II and smug, summer-hyped star vehicles like Meatballs.

Yates' winning recipe uses a lot of stock elements, but he combines them with style. The story is a very ordinary growing-up-in-America line that comes alive only because Yates peoples it with real characters and animates them with genuine humor. Dave Stoler, All-American son, is just out of high school, committed to not getting a job and hanging out with his friends. Not unusual. But this kid also wants to race bicycles. In anticipation of the arrival of the Italian national team, he learns Italian and trains with his ten-speed. Which is to say he rides his bike down the street singing arias, renames the family cat Fellini, and chases coeds as Enrique, the Italian Exchange Student.

You'd think his parents would be upset, and they are; but they also respond with a bit of levity. Dave's mother, bemused, humors his irate father with lines like, "Well, we could strangle him in his sleep." Dad, played by Paul Dooley, keeps up a blustering manner with his family, making those rare moments when he lets out some real emotion very powerful. Occasionally the father-son relationship lapses into Mayberry RFD sappiness, but altogether this is the most believable family since "Leave It to Beaver." It's enough to make you believe in middle America.

YATES IS JUST as successful in creating Dave's friends. Moocher, Mike and Ciro, all potentially bland stereotypes, are well-cast and well-acted. Moocher, short but solid, is one of those kids who's never really going to go anywhere, but he has one of the film's great moments--when an employer tells him, "Be sure and punch the time clock, Shorty," he does, literally, and with style. Mike, played by Dennis Quade, is a pretty standard version of the hot-rodding, tough former quarterback--you last saw him in American Graffiti--but in Breaking Away he's more vulnerable, and more honest. Ciro, the clown with the deadpan expression, is as good as his company--an astonishing set of performances for a gang of unknowns.

Aside from Dave and his friend's antics, the plot is fairly straightforward--Yates builds up to two big races, both rousing enough to get audience cheering. The first brings down Dave's illusions about the Italian racers he's been imitating--one of them sticks his hand pump in Dave's pedals to make him crash because he's starting to pull ahead. The second race is a grudge match for Dave and his friends. They are, for the first time, invited to enter a team in the local college's invitational "Little 500." A long-standing rivalry between college students and the "cutters" (townies) is tested.

In spite of Breaking Away's simple trappings, it is not without substantial themes; and the rivalry between the college and the townies is the culmination of a class conflict Yates has built up carefully throughout the film. Americans, he says, are as class-conscious as their European counterparts, but the manifestations are more complex and insidious than simply the blueness of one's blood.

Yet the American way is blessed in the end--family, competition, team spirit, college and friendship--all are affirmed in Dave's final victory. Yates creates just enough ambivalence to stop short of cuteness, but he knows better than to drop the full weight of the heavy hand of Social Conscience on Breaking Away. He pushes ahead to an upbeat finish.

THE BICYCLE turned out to be the perfect vehicle for Yates. Its simplicity demands precision, but once mastered it has its own grace. Yates' pacing is as exacting as a racer's. His photography is graceful and clean, and his humor is light and fast. The satisfying control and craft of turning the wheels and the rush of flying down hills at 50 m.p.h. are matched in Yates' movie--it's simply exhilarating.