Roy Smalley homered from each side of the plate -- only the 12th American Leaguer to accomplish the feat in one game, and each time with two men on -- to help the New York Yankees beat the Royals, 18-7, in Kansas City yesterday.

Smalley's homer from the left side, off Dennis Leonard (9-4), gave New York a 3-0 lead in the second. He homered from the right side in the sixth off Don Hood.

Smalley, who has 14 homers, joined Mickey Mantle, Tom Tresh and Roy White as other Yankees to homer from both sides in one game.

Asked if he had ever done it before, Smalley replied, "I think so, but I don't remember."

Although the Yankees are 11 games behind East Division-leading Milwaukee and are all but out of the pennant chase, they won their second straight from the West Division-leading Royals.

"I don't know if you can call us spoilers," said Smalley, "but we like to beat good teams. It's fun to play games when something is at stake.

". . . There's a lot pent up inside of us. It's been a bad year. Any time we can put a little streak together or beat up somebody like this, the game becomes more fun."

Dave Winfield drove in four runs with two homers, his 28th and 29th, a double and single. Graig Nettles had two hits and scored four times.

Ron Guidry (14-5) pitched seven innings for the victory. He gave up homers to Frank White, Willie Aikens and Hal McRae. McRae also doubled in a run in the Royals' three-run eighth, raising his major league-leading RBI total to 116.