Belmont boys basketball continued its turn-around season, earning a postseason win Tuesday night, beating the Chelmsford Lions 51-40 in front of an energized home crowd. Head coach Dan Burns said the team entered the night focused and prepared. “We were excited, we wanted to keep our routine and I think we did exactly that,” Burns said. “We wanted to keep the ball. They’re known for double-teaming, so we had to play our pace.” Belmont started their usual five: captains Andre…