THE MOTORCYCLE DIARIES ****

CAST: Gael Garcia Bernal, Rodrigo de la Serna, Mia Maestro, Mercedes Moran, Susana Lanteri, Ulises Dumont

DIRECTOR: Walter Salles

SCREENWRITER: Jose Rivera

He was a passionate rebel, a driven--some say fanatical, even brutal--Argentine who had become a legend long before he was executed in 1967, at the age of 39, by a Bolivian firing squad (with, it would seem, more than a little help from the CIA). That was Ernesto Che Guevara, the famously magnetic partner-in-revolution of Fidel Castro. But it’s not quite the Ernesto Guevara we meet in Walter Salles’ compelling new film, which screenwriter Jose Rivera has woven from Guevara’s autobiographical “The Motorcycle Diaries” and Alberto Granado’s “Traveling with Che Guevara.”

What we have here is a fascinating portrait (by Gael Garcia Bernal, in a star-making turn) of a compassionate, intellectually curious 23-year-old asthmatic medical student whose upper middle-class parents have done an excellent job of catering to his whims. What Ernesto wants, Ernesto gets. And what he wants is to delay his final year at the University of Buenos Aires and take to the road with his buddy Alberto, a biochemist who yearns to see a lot more of his beloved South America before his 30th birthday, which is only a few months away. So the friends--the older a relentless womanizer, the younger a purist who plans to stay as true as possible to his ravishing sweetheart (Mia Maestro)--embark on what they envision as a lighthearted lark, except for a stop-off at a leper colony that doctor-to-be Ernesto is determined to visit.

To be sure, the unseasoned adventurers do frolic on the first leg of their eight-month journey as they rumble and tumble along on Alberto’s smashingly untrustworthy 1939 Norton 500, a bike they have unwisely dubbed The Mighty One. At one point, they are forced to make a hasty retreat from a small town where a married woman clearly views handsome Ernesto as a sex object. As they travel north, however, through Chile, Peru, Venezuela and, especially, the San Pablo leper colony in the Amazon, giddiness gives way to gripping encounters with harsh poverty, disease and social injustice. Gradually, we observe the rage brewing beneath Ernesto’s political passivity and we sense the incredible force he will ultimately bring to an idea that is only beginning to take root in his soul.

As fleshed out by Gael Garcia Bernal, the unforgettable teen-aged Casanova wannabe of “Y Tu Mama Tambien,” Ernesto--later to be Che--Guevara is an astonishing blend of stumbler and saint (far different, no doubt, from the calculating, non-halo-wearing revolutionary Benicio del Toro is expected to portray in Steven Soderbergh’s upcoming version of the Che legend). And Rodrigo de la Serna, as the buffoonish but stalwart Alberto Granado, makes a splendid soulmate. The ripening of their remarkable friendship and their joyful reverence for their native land are what give "Motorcycle" its emotional thrust.

In a time of intensified gimmickry and hardsell, director Walter Salles--topping the impressive achievement of “Central Station”--has made a movie so subtle yet straightforward, so modest yet overpowering, that it seems truly revolutionary. --GUY FLATLEY