Two national champions from Washington, D.C., were upset tonight in the boxing semifinals at the National Sports Festival.

Featherweight national champion Lyndon Walker was beaten by Kelcie Banks of Chicago, a 6-foot break dancer who had two standing eight counts on the top-ranked amateur before the fight was stopped in the second round.

James Harris, the national champion in the light flyweight class, was decisioned by flurry puncher Brian Lonon of Fort Hood, Tex.

Walker, 20, finished third in the Olympic Trials. But at 5 feet 3 he was at a nine-inch height disadvantage against 20-year-old Banks, a 10-year veteran who has emerged this year as an Olympic prospect.

Banks' reach made the difference. Walker tried to move inside to the body, only to take repeated combinations to the head. He received his first standing eight count early in the second round when Banks hit him with a left uppercut that caused his knees to buckle.

The second eight count came moments before the fight was stopped at 2:15 when Banks hit him with another left uppercut and a double right hook that sent him reeling. The same combination ended the fight.

"He caught me with wild punches when I came in," Walker said. "He didn't hurt me. I just tripped moving away. I can't believe they stopped it."

Banks will meet another Washington fighter, Bernard Roach, in the finals Sunday night.

Harris was a quarterfinalist at the Olympic Trials. But Lonon, one of nine U.S. military boxers here, outpointed him to win a 3-2 decision.

Ron Carlisle, a three-time national champion, fell to Craig Pittman in the Greco-Roman heavyweight wrestling division. Carlisle and his wife lost their first child at birth Thursday night and he flew home to Quantico, Va., immediately after his 2-1 defeat.

In other Greco-Roman wrestling, Buddy Lee of Arlington won his first-round match at 135.6. Mike Johnson (198) of Quantico decisioned Mark Van Tine of Baton Rouge.

Pat Ferguson and Gene Ferguson of Cumblerland, Md., had one goal each to give the North roller hockey team an 8-0 victory over the South in the first round of the tournament. Goalie Bobby Thomas of Cumberland was the winning goalie, with 28 saves.

In men's kayaking, Norman Bellingham of Rockville placed second in his heat to qualify for the semifinals.

Bruce Merritt of Ridge, Md., won his heat. Bruce Hartzler of Chevy Chase finished seventh in the same heat in 2:39.04 and goes to repechage.