Larry Holmes stays pent up in the Hilton Hotel trying not to speak, apparently aware that when he does open his mouth, he usually ends up insulting someone.

Only once a day does the former heavyweight champion appear downstairs, to train silently for his title rematch Saturday (HBO, about 10:30 p.m.) with Michael Spinks, a session that is mostly a pantomime of jabbing fists in the air and dancing around to rock 'n' roll. Then he usually disappears as quietly as he came, leaving trainer Richie Giachetti to speak for him and clear up any misinterpretations.

"Okay, so he opens his mouth too much," Giachetti said. "So everyone says he's shameful. How's it shameful? What's so bad when he's just bragging on himself?"

Except that Holmes' way of bragging usually comes at somebody else's expense. Which was the situation today when he had a sportswriter physically evicted from his training session. Then the words just came tumbling out unbidden.

"That's why I keep my workouts closed," Holmes said angrily, after three of his handlers bodily carried 5-foot-8, 68-year-old Dick Young of the New York Post from the room after an exchange of insults. "You're going out in style, Dick Young!" Holmes yelled. Upon which a majority of the other writers present walked out in protest.

Later, addressing a crowd of several hundred at the sparring session, Holmes said, "A lot of people think because they're the press they can do whatever they want, write lies about me. I don't party with them Saturday nights . . . "

So much for Holmes' carefully cultivated low profile this week, part of his informal campaign to earn a nice-guy image. Holmes had not granted interviews to the media for six weeks, and had not made a public statement since his recent comment that Nevada boxing judges were also drunks. "He meant," said Giachetti, "the way they scored was drunk, not the judges." Holmes nevertheless had to apologize for that one, just as he apologized for saying about Rocky Marciano, "If you want to get technical, he couldn't carry my jockstrap."

Holmes made the latter remark in a fit of anger over defeat, the first of his career, the one that kept him from tying Marciano's record of 49 straight victories, and having become the first heavyweight champion to lose to a light heavyweight champion, this Michael Spinks.

With his remarks, Holmes not only lost his long-held title, but what little reputation he had for being a gracious champion. A fighter who has always yearned for admiration, he had set out this week to earn it both in the Hilton Center ring and out.

Earlier in the day, Giachetti had tried to explain how this time Holmes would be going about it all differently. Starting with his attitude, which Giachetti said includes a measure of humility, and what is perhaps a new appreciation of his historical position in boxing.

The fight has been publicized as "Vindication in Vegas." The peg means more to Holmes that mere publicity babble. For the first time in 7 1/2 years, the length of time he held his title, Holmes enters a championship fight as a challeneger. Money, always high on the list of things he liked to earn, will not be what it once was: Spinks will earn $3 million; Holmes will be on the short end at a little over $1 million.

"He wants to get something back," Giachetti said. " . . . That makes you humble, and it makes you hungry."