Stories of the Yetnikoff-Tisch enmity abound, but one recent incident suggests its near-biblical proportions. Yetnikoff, who prides himself on his charitable work, was asked recently by the United Jewish Appeal to help in an urgent fund-raising drive by arranging for benefit appearances by some of CBS's recording stars. Yetnikoff agreed. However, it happens that Larry Tisch, who also enjoys regard as a philanthropist, is on the board of the U.J.A. Yetnikoff now says that he won't help raise funds unless the organization removes Tisch from the board. ''I can produce far more money than he can,'' Yetnikoff says, ''but I won't do it unless they throw [ Tisch ] off. I have not yet begun to fight.''

It was not always so. When Tisch was just a stockholder, sizing up the company in the months before taking power at CBS, he often held private meetings with CBS employees, getting their views on how the company was being run. Yetnikoff was one of those whose counsel Tisch solicited. He called Yetnikoff for information, he stopped by his office, he invited the record president over to his Manhattan apartment. Yetnikoff, obliging, sounded his favorite theme: the company was in a shambles, its management was inept. It was clear that Tisch would soon be in charge, and Yetnikoff felt, his close associates say, that he and his soon-to-be boss established a mutual sympathy.

In the corporate culture of CBS Inc., Yetnikoff, the former lawyer who became head of CBS Records in 1975, had always been a subculture unto himself. He kept the hours that his rock stars kept, arriving late (noon is early), staying late, wearing no tie. He was famous for his bursts of pique aimed at management - why couldn't he have a private jet, like Warner Communications? ''Every record company needs a small air force,'' Yetnikoff would say. His outrages at board meetings were legendary (his boredom, too; he once fell asleep at a shareholders meeting). He was, in other words, a personification of the free-spirited music business within the more staid, gray-suited environment of CBS.

His actual job, it is safe to say, was unlike that of the other heads of CBS's operating groups. Yetnikoff has no particular musicality; he generally does not produce records or sign artists, and his record division, while always profitable, has at times a smaller profit margin than does its nearest competitor, Warner. What he does, and does quite well, is set the tone of the record group, and deal with the sometimes fragile egos of his labels' big stars. In this last regard, he is by all accounts without peer - forever dashing off to California ''because Michael needs me,'' interrupting phone calls because ''Barbra's on the other line,'' hopping the Concorde to Paris for a Cyndi Lauper concert because it's important to her that he be there (''That's loyalty,'' Lauper says).

''I am the guru,'' Yetnikoff says, ''the spiritual leader,'' a function, Yetnikoff often emphasizes, that is crucial in a business ''where the product can talk back to you, where it can scream back at you.''

If Yetnikoff once thought he had a special relationship with Tisch, his perception quickly changed. Yetnikoff says that in their first meeting after Tisch assumed power, the new C.E.O. told him he was closing Yetnikoff's private kitchen and dining room as part of a cost-saving measure. ''Ha! A major cost saving,'' Yetnikoff says, as he escorts a visitor to the contested room to demonstrate ''that it's not exactly the Taj Mahal.'' However, some Yetnikoff associates say what really bothered him was that once Tisch took control of CBS, Yetnikoff became just another executive in a company bound for drastic change. If he had been expecting special treatment from Tisch, he was disappointed. ''Walter's problem with Larry,'' says one Tisch associate, ''was that for the first time, he couldn't whine and cry and get every outrageous thing he wanted. He was told 'yes' or 'no,' and treated like everyone else.''

There emerged the awful realization that, vital though a guru may be, such an individual might be expendable in a corporate environment where excess was frowned upon and waste was a mortal sin - particularly if the corporation were thinking of unloading his operation. What Yetnikoff needed was leverage, and in a brilliant display of corporate gamesmanship, he created it.