There's a bit of deja vu in store for Los Angeles voters.

Just when it looked as if Mayor Tom Bradley was going to run virtually unopposed for a third term, former Mayor Sam Yorty made a last-minute surprise decision to run for the office one more time. Bradley lost his first mayoral bid to Yorty in 1969 but then unseated him in 1973.

Bradley is expected to enjoy an easy victory over Yorty and a handful of virtually unknown contenders.

But insiders say that by raising a number of thorny city issues, particularly crime, Yorty hopes to handicap Bradley in the mayor's expected bid for the Democratic gubernatorial nomination in California next y ear.m