Inspired by the British café racers of the late 1950s, customizers have begun reworking BMW’s air-cooled boxer twins along similar lines. For a greater challenge, Sean Mathis customized a K 100 RS to reveal the engine and other parts that BMW obscured with fairings and covers. “I really liked the single-sided swingarm and wanted to open up the back wheel from obstruction,” he says. He chopped the frame and added a lightweight exhaust, removing more than 100 pounds from the bike’s curb weight, then painted the bike Laguna Seca Blue. “I thought it was appropriate to give it a bright, original BMW color to go with the gold wheels,” he says.