Everyone who knows about "Roots" knows about griots, the walking encyclopedias of African oral tradition, but few Americans have ever seen one.

Saturday night in the Smithsonian's Baird Auditorium, Washingtonians can have a chance to encounter a griot, and some of them may lose their shirts unless they have brought along something else that can serve as a spontaneous gift.

Generosity to griots is in an African tradition that has apparently transplanted to American soil as readily as African music has been transformed into American jazz. Batourou Sekou Kouyate has been traveling through this country for several months in a beat-up old station wagon, covering some 10.000 miles and staying in American homes. He has found that he has many friends here and doesn't find it terribly different from Bamko, the capital of Mali, where he lives, except that you don't expect quite so much from Americans. "In my country," he said in an interview at the Museum of African Art, "I can go with my kora to anyone's house and say "I want you to help me,' and with three wives and 10 children, I could move into that house and spend my whole life there, and when I die my children could stay there after me. That is what we call nobility."

Sunming up the grint's relation to his clients, he said, "I praise their names and they present me with gifts."

Some griots are primarily or exclusively talkers. Kouyate is a talker in his private activities as a griot, serving various Malion families that have a special claim on him, but in his public performances he is primarily a musician. He is one of the world's leading masters of the kore an African instrument that looks and sounds something like a harp planned on top of a drum, and his performance around the United States (mostly on campuses) have excited audiences to will enthusiasm. Some fans, following the African tradition of presenting personal gifts to a muscian, have torn their shirts off and given them to Kouyate.

"The president of Knox College gave Batourou Sekou his necktie," recalls Charles Bird, a linguist from the University of Illinois who has been driving Kouyate around the country from concert to concert. "This was a great honor. He says he will keep the necktie and give it to his son, but he doesn't know what to do with the shirts." Kouyate dresses in an African style to which shirts and neckties are wholly alien.

The best-known part of the griot's work, remembering and retelling vast quantities of oral tradition, it part of Kouyate's training but not part of his public performances. "I would say he is like a living library rather than a walking encyclopedia," says Bird.

Kouyate agrees. What is preserved in his memory from his people's oral tradition, he says, would take two months just to give a table of contents and, "If it were all put into books, the books would fill this house."

"This house" is the Museum of African Art not as big as the Library of Congress two blocks away, but quite spacious. The claim is probably a modest one.

Bird speaks, for example, of the epic of Sunjatta, the emperor who built the Mali Empire in the 13th century and a figure in the history of West Africa comparable to Alexander the Great in the history of Europe and the Middle East. Various versions of this epic exist in the oral tradition, Byrd said, it is one small part of a griot's knowledge. It can be condensed to three hours in the telling, and one griot has recorded a version eight hours long, but there are also versions that can run as long as 21 hours.

Besides material like this, a griot knows family histories, stories and fables, songs, proverbs and even jokes. And this reference service is only a part of his social role. In the families with which he is affiliaed, a griot is the marriage broker, for example, and serves at funerals and other ceremonial family occasions. One American analogue of Kouyate would be Chet Atkins, perhaps, - but only if Atkins were also a justice of the peace, notary public, master of ceremonies . . . and the Library of Congress.

Whenever a member of one of the families with which Kouyate is affiliated asks him for one of these special services traditions requires him to fulfill it; he play at an average of five or six family occasions per week in addition to his work with a government sponsored national musical ensemble, and each of these appearances involves three or four visits to make arrangements.

His work for the government involves rehearsing until about 11:30 in the morning, he says, and then "it would be hard to say" what he does for the rest of the day. The "hard to say" part is the real business of being a griot.

Kouyate, who is 60 years old and looks to be in his middle 40s, speaks some French but prefers to talk through an interpreter in his native Mandinka. It is a curious experience for one who does not know the language to listen to a stream of uncomprehensed syllables punctuated occasionally by a technical term in French - "onze heuers et demie," for example. The idea of calibrating time by the minute is alien to Africa; the Mandinka language disignates times of day with words that describe the shifting qualities of daylight.

Kouyate was brought to American as avisiting lecturer at the University of Indiana, teaching an interdisciplinary course on African culture, music and languages.

During the fuel shortage in the Midwest last winter, Bird recalls, the University of Indiana was closed for three weeks, and "during that time, Batourou Sekou's apartment was transformed into a sort of African compound. Almost any time, day or night, there would be three or four musicians sitting around in various corners practising the kora, and from time to time the women would come out of the kitchen with great, steaming bowls of rice. We would eat African style - you take a handful of rice and mold it into a shape that is convenient for eating."

While he was teaching at Indiana and since the end of the term, Bird says, the old Chevy wagon has logged 10,000 miles going back and forth to concerts sponsored by the African Studies and Black Studies departments of various colleges and universities.

"We wanted to save as much as possible on expenses, so I bought this old ear for $1,000 and ran it, into the ground," he recalls. "It had 90,000 miles when we go it, and now the motor is really shot."

During their musical barnstorming tour, Kouyate and his entourage (Jontan Tunkara, his wife and a singer; Nantenegue Kamisoko, a cousin and a singer, and Mamadou Kante, a Malian graduate student at Indiana who is serving as a translator and general expediter for the trip) have stayed in the homes of friends - their own or Charles Bird's - rather than at hotels, partly to save on expenses but also because they would like to have access to kitchen. "American food does not exactly thrill them," Bird explains.

Saturday night's concert will follow a form something like a traditional family ceremony, with Kouyate playing the music while the two singers sing the words of traditional stories, with Bird giving translations and explanations - also accompanied by Kouyate's music. Some of the people in the audience will sung to individually and will give presents; they will want to, although it is not necessary to take off your shirt.

"This matter of gifts may seem mercenary, but it's not," Bird explains. "The theory is that the music gives you energy, vibrates in you and sets up a disequilibrium that makes you want to act. Gift-giving is a resolution of the harmonic tension that ha sbeen induced; it expresses your intense feelings in a way that does no harm."

Kouyate wants present a gift, too. He has a kora that he wants to gibe to President Carter - his favorite one, which he made himself, and a veteran of his last European tour - but he does not know that protocol and Mali has no ambassador in Washington at the moment. He feels that there would be great honor for both parties in the offering and acceptance of this gift.