The American jockey had taken one of the less promising of Hong Kong's usually mediocre race horses, a 40-to-1 shot, and brought home in second in a big race. One of the city's prosperous Chinese businessmen congratulate the jockey on his achievement, but it wasn't what he wanted to hear.

"Don't ever congratulate me for coming in second," Bill Hartack advised a friend later.

After about 4,300 winning mounts, including five in the Kentucky Derby, prickly Bill Hartack has come to this mecca of second-rate Australian horses, anachonistic British racing customs and Chinese gambling hysteria to spend the twilight of his extraordinary career. The demands of pursuing his craft at the only American jockey in a crusty, in grown racing fraternity has mellowed him a bit, his friends say, but only a bit.

"One of the reasons I left the U.S.," he said shortly after arriving here 2 1/2 years ago, "was I knew that once I caould get away from the American Press I would be very, very happy because they're so stupic." When asked for an interview by a Washington Post reporter here recently, Hartack politely but firmly refused. His friends say he doesn't seem to miss the glow of the triple crown spotlight.

In this British colony of more than 4 million Chinese, to be one of only 32 licensed jockeys is probably enough celebrity for any man.

Although handicapped by his connection with a relatively small stable, Hartack placed fifth among Hong Kong jickeys in his first two seasons and his mounts continue to draw heavy wagers. The little eight-furlong Happy Valley Race Track here generates a total of $13 million in legal and off-track bets on a good day. It is open about 50 days a year.

"The Chinese are the greatest gamblers in the world," said Stan Freedman, an American textile importer and a Hartack friend who enticed the jockey to come here. "It's in their nature. If I toss this coffee cup in the air, they'll place a bet on it."

Three years ago, Hartack, Now 44, was hustling a dwindling number of still available mounts on U.S. tracks, looking for an elusive sixth derby win that would put him in front of the only other five-time winner, Eddie Arcaro.

He was also fighting the demon that afflicts many other aging jockeys: Weight.

"I was getting tired of reducing," he told a reporter for Hong Kong's racing magazine. "The minimum scale in the U.S. is about 105 pounds and the maximum generally is 122," said Hartack, who hates to diet.

"Once," he said, "I took off 9 1/2 pounds in four hours in the sweatbox.

The standard weights for jockeys are higher here, and Hong Kong was already a refuge for some heavier European and Australian riders. Hartack contacted a newly arrived British trainer, Peter Supple, who was developing a stable that now numbers 25 horses. They got along fine, and Hartack managed to sell himself to the tradition-bound Royal Hong Kong Jockey Club, a feat longtime American residents here consider something of a miracle., even with Hartack's reputation.

"I think Americans are still treated like fifth calss citizens," said one New York businessman who has lived here 16 years. How could Bill Hartack, the relentlessly honest jockey who had alienated many an owner by saying just what he thought of his horses win acceptance from the very British, religiously amateur sportsmen of the jockey club?

"First," said Freedman, "because Bill has mellowed. Second, because he's intelligent enough to realize he has to go along with some things, like going out to dine with an owner, to get along."

And, his battle with American reporters behind him, Hartack won admirers in the local press. "I would say he's one of the most straight forward blokes in racing," said Jim McGrath, the racing correspondent for the English-language South China Morning Post. "I couldn't speak too highly of the man."

Determined and thoughtful about his work, known for his expert use of the whip, Hartack has done well with the motley assortment of geldings and fillies that make up the 400 to 500 race horses kept there.

McGrath said: "Horses run for him."

Hartack had a fine start in his first season - October, 1974, through May, 1975. Twenty of his 90 mounts were winners. The next season, he had 14 winners with 146 mounts. This season, he has had a slow start, only three for 58.

For a jockey who was making more than $200,000 a year in his prime, this brings in very small change, perhaps only about $20,000 a year for the riding alone. However, Hartack, a life-long bachelor, has a reputation for being very careful with his money.

The rules here forbid jockeys from gambling, although some do. It is hard to resist getting caught up in the excitement of the once-or twice-a-week race days that draw 35,000 to 40,000 people at the little race track not far from the heart of Hong Kong's central business district. Many more thousands flood the 114 off-track betting locations and place most of their money on intricate longshot combinations like the "six chains together," picking the first or second horse in each of six races, or the "four times lucky," selecting the first through fourth horses in one race.

The Chinese gamblers here cannot, perhaps, match the fervor or their brethren in Singapore, where the race track packs them in just to listen (and bet on) loudspeaker broadcasts or races in neighboring Malaysia, but Hong Kong comes close.

The jockey club now takes in about $400 million a year, 10 per cent of which goes to the government, and another $10 million or so to the club's charities.

The race track and the club's shining new 16-story office building with one floor given over to a phone bank for the club's "telebet" customers, are located in what the Europeans here still call "Happy Valley." The official Chinese name is "Horse Racing Ground."

On this little track. Hartack arrives each morning to exercise the horses, something his colleagues in the states, may find hard to believe. On Saturday race days, he is there to duel with Garry Moore, the Australian jockey whose No. 1 ranking in Hong Kong is aided by the his ability to pick from the horses in his father's large stable.

In his free time, Hartack, a self-confessed womanizer and avid waterskier, finds the holiday atmosphere of Hong Kong to his liking. He lives at the Hilton Hotel and in the offseason, goes hunting in Montana or New Zealand.

"I'll be here two or three more years," Hartack says, but those who watch him work seem to think he'll try to stretch it out as long as he can.

"He loves the game," said McGrath, "and this is the only place in the world where he can still ride."