Muhammad Ali gave the promoters of Friday night's title fight a scare yesterday when, without even a round of shadowboxing to warm him up, he began to spar - without the customary headguard.

An accidental butt or sharp punch might have cut an eye and postponed the multimillion-dollar challenge for Leon Spinks' crown.

It was a glum champion who set out to prove he has not lost his skills, in contrast to Monday when he was hit freely by 19-year-old sparring partner Tony Tubbs.

Ali admitted he had given an unimpressive performance when he asked after yesterday's four rounds of boxing against Tubbs, "Wasn't I 100 percent better today than I was Monday'?'

He was not. Maybe 50 percent better but not 100.

"I was tired Monday," Ali said. "I ate breakfast too late and was sluggish."

Ali said he did not use headguard yesterday because "it made me more serious. It made me be sure to slip punches better." Fortunately, although Tubbs once more appeared to have the better of the four rounds, Ali did not take any blows damaging to his eyes, nose or mouth.

He insisted, "I am in better condition for this bout than I was for my bout in Manila with Joe Frazier (the one which critics say marked the beginning of the sharp erosion of his reflexes).

"I trained only two months for my first bout with Spinks. I have trained six months for this one. This time I have desire (the chance to be the first to win the heavyweight title three times).

"My weight is better, I am about 223 (he weighed 224 1/2 for this first bout to Spinks' 197).

"My muscle tone is better."

Once more the impression gleaned at Ali's sparring session was that if he were trying to convince spies from Spink's camp that his reflexes are dull he was close to qualifying as a professional actor.

He did not talk to the audience of several hundred who cheered his entrance, as he did Monday. Ali was all business as he started the first round dancing on his toes and jabbing at Tubbs. Yet Tubbs was able to keep on top of him merely by plodding flat-footed. The former champion did appear to be slightly faster than the day before.

In the second round, Ali began dancing again but soon came down to a stalk, jabbing at Tubb's body. He was outjabbed by the youngster and when he tried an overhand right it seemed to slow. Tubbs popped him with a showy one-two combination to the head and Ali managed a sharp left hook to the jaw.

Tubbs appeared to have the better of a light flurry of punches in the third. In the fourth and final around, Ali worked himself up to a lively exchange of blows to the head and had the better of it as former World Boxing Association champion Jimmy Ellis shouted instruction to Tubbs to work Ali hard and Wally Muhammad urged on the former champion.

Ali "won" the round but was not at all dominating.

Before the sparring session a member of his entourage favored quite a few members of the media with what Ali said was his response to criticism of Monday's sparring.

"You will see who is great when the small gloves (eight ounces versus the 14-ounces gloves used in training) and no headguard is on, the crowd is big, the pressure is on and all . . . is on the line.

"The real professional comes out and then, damn what has happened in practice. This is where it will count and we will see who wears the crown."

As usual, gossip was rife that Ali is angry with Dr. Ferdy Pacheco, who worked in his corner for years before the first Spinks bout, charging Pacheco, with implying the former champion was "all washed up" because he advised him to retire; Bob Arum of the Top Rank Inc. televsion promotion firm was having problems trying to convince the local "live" promoters that the first few rows of ringside seats should be reserved for the media and ring officials, and that the entourages of both fighters have been complaining because they have been put on vouchers, limiting the amounts the hotel will pay for their expenses as part of the agreement to headquarter here.

There is a story ciruclating that Spinks has told intimates that he does not remember what happened in the 10th round of th first fight, but that Ali did not know he had Spinks out on his feet or just couldn'd deliver a knockout if he did know.

Ali's trategy reportedly called for him to try to make Spinks punch himself out by hiding behind a rope-a-dope defense in the first five or six rounds, then come on strong against Spinks in the eighth, ninth, and 10th.

It worked to a degree, but Ali tried.

Now it is expected he will try to take Spinks out in the early rounds, knowing that at age 36 and aware of Spinks' proven endurance at age 25, he may as well gamble.