NEW HAVEN, Nov. 18--The Yale junior varsity football team made no sustained drives against Harvard today, but it hardly needed to. Four times the large Eli line threw some key blocks, and four times Yale backs broke away for long touchdown runs.

The only short score of the afternoon was Bob Corry's quarterback sneak just four minutes before the end, making the final score 31 to 0. In completely outplaying the Crimson, Yale climaxed an undefeated season and won the junior varsity Big Three crown.

Jim Hust's 31-yard score was the only touchdown of the first half. Three times crucial tackles by the Crimson's Joe Stein, Ed Harding and Al Steiner stopped Yale drives deep in Harvard territory.

The second half had hardly started, however, when Hust smashed over left guard, cut to the right sideline and ran 86 yards for the Eli's second touchdown. The Crimson failed to make a first down after taking the kickoff, forcing quarterback Jack Hennessy to punt from his own 20 yard line. Bill Williams took the punt, and aided by a key block from end Dick Skewes, raced 56 yards down the left sideline for another score.

By the final quarter, Yale linemen Ed Moore, John Kohr and George Darmstaedter were opening large holes and smothering the weak Crimson offense. Several times, quarterback Hennessy was thrown for large losses in attempting to pass.

Just before the third period ended, Crimson halfback Joe Guglietta made the most spectacular broken field run of the afternoon in going 66 yards to the Yale 25.

The Elis took the ball on a fumble, however, and a few plays later Jim Kinney took a pitchout 50 yards, helped by heavy interference. Corry made the only conversion of the game to make the score 25-0.

The final Yale score came after the Crimson had failed to complete a fourth down desperation pass on its own 26.

The Elis bucked to the one yard line in four plays, and Corry completed the rout with his quarterback sneak. The shutout marked the third game this season in which the Crimson has failed to score.