Three easily identifiable lights: green û Fi2000R is adding more fuel, making the air/fuel ratio approximately 14:1; green and yellow lights û these lights will be on in unison when throttle is open more quickly and air/fuel mixture is approximately 12.5:1; red û light comes on and stays on as long as the Fi2000R follows the fuel curve while adjusting to approximately 12.8:1 air/fuel ratio, which is where the engine will produce its best full-throttle power Corrects lean air/fuel mixture problems; eliminates overheating, backfiring on deceleration, hesitation on acceleration or an uneven cruising rpm Can be used with any exhaust system on the market today. FI2000R VULCN 1600 CL/NMD