To avoid disappointment, don't think of "Street Music" as a Big Deal.

Though this is a likable and promising first feature, written and directed in San Francisco on a budget of about $600,000 by Jenny Bowen, it is nevertheless flawed and tentative enough to call for strictly modest expectations.

Bowen shows a knack for incidental character humor and a confidence with actors that could carry her further professionally than most novice filmmakers, but her script develops perceptible sags as the focus of attention fluctuates between a love affair and a social crisis that remain to be persuasively, securely interlocked.

Bowen began the script when she became friendly with a group of elderly tenants who were struggling to save a North Beach hotel called the International from demolition. "Street Music," now playing at the Circle MacArthur, is set in a seedy transient hotel called the Victory, on Eddy Street in San Francisco's Tenderloin district.

There's an incongruous set of tenants among the few remaining residents: an aspiring little hoofer-belter called Sadie Delaware (Elizabeth Daily, seen earlier as the girl Griffin O'Neal recruited as his assistant in "The Escape Artist"), who works as a street entertainer and lives with her boyfriend Eddie Beagle (Larry Breeding, a physically impressive and magnetic young actor whose career was prematurely ended by a fatal auto accident), a disillusioned Berkeley radical drifting into a humorously cynical middle age while employed as a tour bus driver.

Eddie's inertia has supposedly kept the couple lingering at the condemned Victory, inhabited largely by pensioners, far beyond Sadie's expectations, and their relationship is meant to skid to a breaking point at the same time the tenants are mounting a last-ditch campaign to save the building and avoid relocation.

Unfortunately, the vicissitudes of Eddie and Sadie never seem intimately connected with the community-action subplot, which is rather more compelling than the romantic plot. One always feels as if the lovers have been inserted in this setting to prevent the instant rejection that might have met a script concentrating on the plight of a group of old folks.

While the material always lacks dramatic coordination and suspense, the movie is fairly diverting and amusing from scene to scene. The elderly supporting characters are well defined, and sometimes their behavior reveals authentically funny, endearing crotchets, notably those of Marjorie Easton as a gaunt, daft widow named Mildred, who likes nothing more than staging parties for her beloved horde of kitties. The best single moment in the film is her helpless, baffled reaction to the refusal of these cats to stay put when she tries to pack them inside a large cardboard box. "Uh-oh," she chirps endearingly, as they hop easily out of the box.

Relatively free of patronizing fondness for its beleaguered older characters, "Street Music" makes a far more discreet and credible appeal on sentimental-crusading interest than an import of a few years ago called "Home Sweet Home," which depicted a revolt at an old folks' home. Bowen doesn't seem comfortable with righteous indignation, and there's no attempt to portray the Victory as a garden spot, the tenants as paragons or the authorities as uncaring brutes.

Her discretion is particularly apparent in the handling of a character such as the young hotel clerk Monroe (D'Alan Moss), whose slightly fanatic longing for political confrontation is balanced by an endearing boyish earnestness.

Since Sadie and Eddie (whose names smack a little stickily of Damon Runyon characters) don't really belong at the Victory and since the tenants' protest seems a proud, honorable gesture at best, it's difficult to perceive any poignant emotional correspondence between the end of the affair and the end of the building.

Bowen seems obsessed with a different problem when she's dealing with the lovers--Sadie's alleged need to declare her emotional independence, which is also imagined to be the key to her professional success. Sadie is evidently unmoved when Eddie makes a futile gesture of his own in support of the tenants' protest, inevitably losing his job in the process. Evidently, we're meant to swallow the notion that he doesn't measure up to youthful, ambitious Sadie, and Bowen gives her film a denouement lifted rather embarrassingly from "Funny Girl."

The costarring mismatch really won't support this form of exquisite humiliation. Breeding may seem a little old to be consorting with a pep-club pepper pot like Daily, but his large, craggy, amused mug holds the camera in a firmer grip than her baby-faced shininess and stridency.

Moreover, it's easier to believe that Eddie might have a career in show business, especially against a San Francisco setting; his way of amusing himself on the job--inventing preposterous stories about the city's scenic attractions--might be adapted into a comedy act with far more potential than Sadie's short-legged, heavy-footed tapping and brassy wailing.

The genuine sense of loss in "Street Music" derives from Breeding's death; it seems a shame that a guy with this much face and presence didn't get the chance to capitalize on his first leading role in a feature film.