Some past champions got more than they could handle today while others continued to breeze through the competition at the second day of action at the   Asics Junior Freestyle Championships at the FargoDome in Fargo, N.D.    Brock Zollinger (105.5) of Idaho, hit a speedbump on his quest for a double championship as he lost his first freestyle match to Michael Galisky (105.5) of Pennsylvania, 7-5. The match left Zollinger at 3-1 and Galisky standing at 4-0.    Returning champion Nathan Kendjorsky (114.5) of Ohio also took a loss today as teammate Nathan Browning beat him 10-8. Kendjorsky is still alive at 6-1, but Browning was eliminated after losing two matches today.    Other familiar names have had little trouble though. Junior Greco-Roman champion Gabriel Mooney (98) of Minnestoa has won all four of his bouts by 10-0 technical falls.     Steven Mocco (275) of New Jersey is running through his competition in typical steamroller style, closing all five of his matches in the first round with wins by pin and technical fall. He has yet to allow a point through the last three Junior National championships and doesn't appear to be threatened any time soon.     Nick Simmons of Michigan, a legend in his own right at the Junior Nationals, continued his quest for a fourth consecutive championship in typical fashion, allowing only one opponent to score en route to a 7-0 tournament record.     Action in the FargoDome continues until Saturday night when the Junior Freestyle Championship matches mark the last of eight days of wrestling at the largest wrestling tournament in the world.