Carbs and jets aren't entirely gone, but they're going. According to Gene Thomason-head man at Gene's Speed Shop in Torrance, California-having Harley's Stage 1 fuel map flashed onto your stock black box is fine as long as you're taking about a stock bike with a street-spec Harley-Davidson exhaust system. If you're using some other street-legal aftermarket system-something from Vance & Hines, for instance-you're better off with a fuel controller from the same source. "That way you know everything is going to work together, because all the homework is already done," Thomason says. "If you have aspirations of doing other stuff to the engine down the road, like hotter cams, high-compression pistons or more displacement, the next step is a Harley Screamin' Eagle Race Tuner kit or a MasterTune ECM reprogramming tool." Both give you more freedom to re-map the stock control module, making either one a better bet for getting the most out of a really big twin. Thomason prefers either one to a piggyback fuel-control box. However, that freedom assumes a certain amount of experience with the care and feeding of heavy-breathing fuel-injected twins. Inexpert tuners are better off letting a professional tuner handle such an engine's increased appetite.