"The Frisco Kid" is a schlepper, by turns farcical and mawkish, about the misadventures of a saintly schnook . The would-be endearing protagonist, Avram Belinski, is a foolish young rabbi who graduates without distinction from a Polish yeshiva and treks across America to reach a promised congregation in San Francisco, circa 1850.

Landing in Philadelphia, Belinski blunders listlessly westward, surviving a mugging, a slaphappy spell as a railroad laborer, a blizzard, a posse, a tribe of Indians and redundant showdowns with the bad hombres who mugged him in the first place.

The finished film obliterates whatever promise of novelty and human interested existed in the basic idea of Belinski's culture shock. If the rabbi's odyssey was embryonically appealing, the filmmakers have nurtured it along pact from an elephant trying to hatch a robbin's egg.

As Belinski, Gene Wilder seems an obvious, bobby-trapped choice to impersonate a harmless, pious innocent. He locked himself into a schnooky strait-jacket in his last comedy vehicle, "The World's Greatest Lover," and perhaps it's too late to rediscover the crazy, sponltaneous comic impulses that might liberate him from this impotent stereotype. Although Belinksi is ostensibly more ethnic than any other schnooky comic hero one can recall. Jewish clowns like Jerry Lewis and Denny Kaye wore out the mold long before Wilder eyes touched it. They also had plenty of competition from gentile boobs, like Arthur Lake in the Dagwood series or Donald O'Connor in the Talking Mule series.

Hidden behind a curly profusion of beard, Wilder's face is difficult to place. His performance becomes narrowed around his sorrowful blue eyes, emphasized so indiscreetly that the soulful, suffering aspects of Belinski grow insufferable.The low point: A tear dribbles out of one pale blue orb when Wilder addresses a little sermon on True Friendship to Harrison Ford, unluckily cast as a line bandit who takes pity on the alien tenderfoot and helps conduct him safely to the Golden Gate.

Evidently no one balked at Wilder's shocking inability to do an amusing dialect, although the presumptive verbal humor in the script derives almost exclusively from dialect jokes, liberally seasoned with Yiddish exclamations and naughty words. Here's the prevailing Wilder sound: "Please don't do dis." Take my accent, please!

Several exhibitors have feared that the Yiddish expressions will automatically sink the movie with a mass audience. A fleeting acquaintance with show-biz Yiddish will suffice to render most of the jokes decipherable. The fundamental problem is that the jokes aren't worth getting.

Robert Aldrich is an awesomely inappropriate choice to direct an ethnic Western comedy. Nothing in the material appears to stimulate - or profit from - Aldrich's erstwhile proficiency with violent or cynical entertainments.

Recalling the noted Aldrich movies - "Kiss Me Daddy," "The Big Knife," "Apache," "Vera Cruz," "Whatever Happened to Baby Jane?," "Hush, Hush, Sweet Charlotte," "The Flight of the Phoenix," "The Dirty Dozen," "The Killing of Sister George," "The Longest Yard" - his association with "The Frisco Kid" makes no sense. Judging from the film, Aldrich never figured out what he was doing there either.

Of course, the movie business has specialized forms of inertia, and this production derived from an original screenplay that gathered dust and lapsed options for many years before finally getting a green light. Once upon a time the story was intended for Mike Nichols, who might have done something endearing with it, once upon a time.

The exposition is also strewn with bafflers. They begin with the very selection of Belinski, an undistinguished scholar, for what appears to be a prosperous bourgeols congregation in Gold Rush San Francisco. It would be easier to imagine his seeking a rural immigrant community a generation or so later.

Why is the rabbi shown hungrily chasing a wild bird and then later identified as "a man who carries no knife"? During production the movie was called "No Knife8," but what did this Orthodox rabbi expect to butcher game with once he'd caught it? What does he mean when he begs the bird, "I don't want to hurt you. I just want to make you kosher"? How? The Jewish dietary laws might indeed complicate Belinksi's journey, but the constraints on him and options allowed him should be clarified from the beginning, even for the sake of farce.

In a similar respect, why should Ford, a prairie-wise armed robber, elect to catch fish by shooting them in the river from a great distance away? He enjoys wasting bullets? He enjoys wasting fish? Anyone out there in the comedy-writing trade know the difference between stupid and funny? CAPTION: Picture, Gene Wilder in "The Frisco Kid."