Madison Bumgarner homered in his second straight start and struck out six in 6 1/3 innings to lift the San Francisco Giants to a 6-4 win over the Pittsburgh Pirates on Friday night. Bumgarner crushed a Jeff Locke (6-8) fastball 418-feet over the wall in left field in the second inning, a two-run shot that gave the Giants an early four-run lead and all the cushion Bumgarner would need on the mound. Bumgarner (15-6) allowed two runs on five hits, walking one while winning his fourth consecutive decision.