It has always been one of those unanswered questions: Did Rock Hudson know he had AIDS when he kissed Linda Evans on "Dynasty"? Sara Davidson, who has written a biography of Hudson that is being excerpted in the current People magazine, writes that he did know and agonized over whether he should go through with the kiss. Davidson writes that Hudson gargled with mouthwash and used a spray just before he kissed her and later said to his secretary, "The kiss is over with. Thank God," according to Davidson.

Davidson also says that Hudson, who told only his closest friends about his sickness, had someone else write longhand anonymous letters to former lovers warning them they might have AIDS. The letters said, "Hi, this note shall remain anonymous for obvious reasons. Since we have had intimate sexual contact where sperm has passed between us, I feel it is only fair that I tell you that I have found out I have AIDS." He continued, "I am most sorry to tell you this. I suggest you have tests made to make sure you're OK." And Now, Bike Aid

Hunger and poverty are the focus of still another national fundraiser, this one on bicycles. What next? Bicyclists are on the roads next week in a cross-country Bike Aid to help poorer nations. A core group of 100 cyclists has signed up to pedal across America with a goal of raising $300,000 to fight hunger and poverty by having other riders, also with pledges of money, join them on six routes.

The cyclists are scheduled to begin in four West Coast cities June 16 and from Houston and Tampa July 16. They are all scheduled to meet here Aug. 5 and then cycle to New York City for the final celebration Aug. 11 at the United Nations building. The organizer, Nazir Ahmad, a student at Stanford University, says he got the idea from the success of Hands Across America, the Live Aid concerts and the Farm Aid concert. End Notes

Bob Dylan, the reclusive folk-pop star, who for a time in the late 1970s became a fundamentalist Christian, has for the past four years been living and worshiping with ultraorthodox Hasidic Jews. Members of Brooklyn's Lubavitcher community told the New York Daily News that Dylan, 45, has been taking instruction from Talmudic scholars. Dylan will not respond to questions about his religious activities . . .

Marla Hanson, the model whose face was slashed Wednesday night by two razor-wielding assailants in New York, left the hospital yesterday. Hanson, who received more than 100 stitches, was discharged "in good condition" and "her doctors are positive about her recovery," said a hospital spokeswoman . . .

Fashion designer Perry Ellis, who died May 30 at 46, has left an estate of at least $900,000, which will be put in trust for his infant daughter, the child's mother, his mother and a friend. In the court papers, Ellis left his possessions to be shared by his 19-month-old daughter, Tyler Alexander, and her mother, screen writer Barbara Gallagher of Brentwood, Calif.; Ellis' mother, Winifred Ellis Waldbauer, of Portsmouth, Va., and Robert McDonald, president of Perry Ellis International . . .

Sylvester Stallone, whose well-oiled, water-sprayed muscles are so much a part of his acting talent in the "Rocky" and "Rambo" movies, says he has a different ambition. He recently told a group of reporters that he wants to do something as "adventurous and questionable" as author/poet Edgar Allan Poe. Poe was a sickly, frail, brooding writer given to bouts of drinking, but who spent very few hours on Nautilus exercise equipment. Edgar Allan Poe with biceps . . .