With old reminiscences, new calls to arms and references to long speeches, about 150 friends and admirers of Hubert H. Humphrey honored the late vice president here yesterday.

The outdoor ceremony to unveil a bust of Humphrey brought together Chief Justice Warren E. Burger, former vice president Walter F. Mondale, former United Nations ambassador Jeane J. Kirkpatrick and Virginia Gov. Charles S. Robb.

Although they hail from different parts of the political spectrum, all, as Burger said, remembered Humphrey as "a great human being."

"Even though we didn't always agree, he enriched my life," remarked Burger, who said he first met Humphrey when he was a lawyer for Macalester College in St. Paul, where Humphrey taught political science. "It was one of the richest friendships I've had in my life."

Humphrey, who would have turned 74 last week, died of cancer in January 1978. The bust, by Mexican artist Gabriel Ponzanelli, was presented to the Hubert H. Humphrey Cancer Research Center of the Boston University School of Medicine.

The ceremony was held in the shaded back yard of Meridian House, a center for international cultural exchanges and education programs on Crescent Place NW.

"Somewhere up there, Hubert is enjoying this ceremony," said Mondale, who followed Humphrey to the U.S. Senate from Minnesota and, like Humphrey, became vice president before losing a bid for the presidency as the Democratic Party's nominee.

"As I speak here, Hubert remains silent," Mondale continued. "How many times I wished it was the other way around." Then Mondale himself invoked some of Humphrey's fervor.

"In these days, when our leadership would have us look the other way as poverty and hunger increase, when we have a government retreating too far in the fight for civil rights and women's rights . . . let us renew our commitment to the compassion and decency that marked Hubert's career," Mondale said. "The sick, the elderly and the minorities must never be allowed to suffer alone . . . . That is his message to us today."

Kirkpatrick, who recently became a Republican but was a long-time Humphrey supporter, offered similar praise, but without criticizing President Reagan. She said Humphrey's "empathy was as broad as the human race," and praised him for helping to "spark . . . the civil rights revolution" and enact Medicare and the Peace Corps.

In a letter read at the ceremony, Reagan said that Humphrey was "renowned for his concern for his fellow man and for the uplifting of the human condition."

Frances Humphrey Howard, Humphrey's sister, and his son Hubert H. Humphrey III, attorney general of Minnesota, unveiled the bust.

Howard quoted a letter she said she received about her brother from Eric Remming, 15, of Mahopac, N.Y.: "Out of all the politicians I've read about and know, I believe Hubert Humphrey was the most caring and nicest one of them all. I am sure you feel the same way I do."

Other speakers included Robb, who met Humphrey through his father-in-law, President Lyndon Johnson; Rep. Claude Pepper (D-Fla); Rep. Corinne C. (Lindy) Boggs (D-La.); Joseph John Jova, president of Meridian House International; John B. Amos, a major contributor to Humphrey's campaigns who donated the bust to Boston University, and two university officials.

As the ceremony ended after almost an hour and a half, Howard declared, "This is a real Hubert Humphrey day. Nobody's ever had a dedication that lasted more than 20 minutes, but we did it."