"Escape From Cyberia . . . A Virtual Odyssey," the big-hearted, cheerfully amateurish and generally endearing musical comic book on racism from the San Francisco Mime Troupe, arrived at Los Angeles Theatre Center on Thursday. If you want to see Buck Rimfire, the right-wing radio host who supports the "three strikes and you're dead" anti-crime law, go up against Sister Double Melanin, the "Afro-centric hate monger" who says "three strikes" equals genocide for black men--you have only tonight and the Sunday matinee left to do so.

"Thanks for sticking up for white people!" says a call-in listener from Del Mar Vista to Buck's radio show, pleased with the host's support of Proposition 187, which would take away most public benefits for illegal immigrants. "Before you know it," continues the caller, "we'll all be speaking Spanish! They'll rename our cities!" Buck is reassuring. "I'm sure you speak for millions of people," he says.

For the thousands of people who like to laugh at those millions, "Cyberia" is a swell place to be. On a ramshackle stage with trapdoors and a small turntable, the sets twirl by, as adorably cheap-looking as the costumes.

Bruce Barthol's rock songs, with titles like "My Life's a Crock" and "You're So Screwed," also have a delightful impromptu quality. This is clearly play time, even if the ideas at play are deadly serious.

The peripatetic Troupe has been wresting political issues straight from the day's headlines since 1959. Its home base is indeed San Francisco, but it has never practiced mime in the Marcel Marceau sense of the word. In 1987 the troupe won a special Tony Award for excellence in regional theater.

The spirited cast keeps popping up in surprising new roles, wearing some hilarious hair piece or prop, like an amply padded butt. Velina Brown is particularly good as Sister Double Melanin, a female Farrakhan who learns repentance, and as a seventh-grader who can't read the instructions on the ATM machine he would like to burgle.

Along with spirit, the troupe and its followers hold on to some of the naivete of its 1960s radical roots. "Escape From Cyberia" asks us to consider that a good kid who tries to protect a girl from being robbed and whose motives are misunderstood could end up a victim of the controversial "three strikes and you're out" sentencing law.

In another subplot, two teen-agers have a meaningful relationship on the Internet, in the nameless, faceless, raceless universe that is cyberspace. Unbeknown to them, they have another relationship in real space: victim and would-be mugger. Once they find that out, the friendship is over, at least temporarily. Only in the cartoon universe of the Mime Troupe could these two friends be reunited as fully as they are here. Oh well, it will have to do until the real world gets funkier.

* "Escape From Cyberia," Tom Bradley Theatre, Los Angeles Theatre Center, Saturday, 8 p.m., Sunday matinee, 2 p.m. Ends Sunday. $17. (213) 387-2800. Running time: 1 hour, 30 minutes.

Michael Gene Sullivan: Malcolm, teen-ager in crisis, others

Rebecca Jane Klingler: Zoe, teen-ager in crisis, others

Velina Brown: Sister Double Melanin, others

Arthur Holden: Buck Rimfire, others

Amos Glick: Max, others

Keiko Shimosato: Rose, others

Gregory Tate: Reporter, others

Eric Crystal: A mellow dude, others

Claudia Paige: A New Ager

A San Francisco Mime Troupe production. By Ellen Callas, Michael Gene Sullivan, Gregory Tate and Joan Holden. Directed by Ed Holmes. Music and lyrics by Bruce Barthol. Set backdrop design by Charles Neifeld. Stage design by Daniel Chumley, Charles Neifeld, Harvey Varga. Costumes by Lorenza Elena Marcais. The band: Cherie Chooljian, Eric Crystal, Claudia Paige.