Bates Motel remains one of the best-kept secrets in American sports.

The most talented thoroughbred in the country, and probably the best since Spectacular Bid, he wins races with the panache of a genuine superhorse. But because he has never competed in New York, he has never received much attention from the media or recognition from the public.

His appearance in the Woodward Stakes at Belmont Park has stimulated minimal interest. None of the television networks is covering the race. To attract some local attention, the New York Racing Association publicity department resorted to hanging a shower curtain near the colt's stall. (In the movie, "Psycho," Tony Perkins slashed Janet Leigh to ribbons while she was taking a shower at the Bates Motel.)

After Saturday, however, no such gimmickry should be needed to make the public aware of Bates Motel, for the $200,000 Woodward is the perfect showcase for his talents. In this prestigious race, which has produced an Eclipse Award winner in eight of the last 10 years, he will be facing the best horses in the East--Deputy Minister, Island Whirl, Slew o' Gold and others. When he is finished with them, even the most cynical New Yorkers should not have any doubts about how good Bates Motel is.

Although racing fans at Belmont are likely to be excited by Bates Motel, the most interested observer of his performance will be an insurance firm, the Chubb Group. When the New York Racing Association decided to offer a $1 million bonus to any horse who sweeps its three-race "fall championship series," it took out an insurance policy to protect itself. The possibility that any horse could win the Woodward, Marlboro Cup and Jockey Club Gold Cup seemed remote. No horse had ever done it before, and earlier this year no horse in the country appeared capable of accomplishing such a feat.

But then Bates Motel emerged from obscurity and became a star in California. "He always had the breeding to be a good horse," trainer John Gosden said, "and we never gave up on him. He really started to develop late last year, and it's really gratifying to see the kind of horse he has become."

After a relatively undistinguished season as a 3-year-old in 1982, Bates Motel has won five of six starts this year, losing on a sloppy track that he clearly couldn't handle. He dominated his rivals at Santa Anita in the winter, then returned to competition at Del Mar last month and routed a top horse, The Wonder, by seven lengths in sensational time.

Then he came east for the Monmouth Handicap, and he made a believer of everybody who saw him there. Running sixth as he entered the final turn, he swept around the field on the turn, with only minimal urging from jockey Terry Lipham, and scored a 2 1/2-length victory over Island Whirl with consummate ease.

His major competition in the Woodward is likely to come from Deputy Minister, the 2-year-old champion of 1981 who has been revivified at the age of 4, but most likely no one will offer Bates Motel any real competition. The 1 1/8-mile distance of the Woodward is perfect for him. The sweeping turns of Belmont are ideal for a horse with his running style. After Saturday, his brilliance will not be a secret any more.