I'm using yamaha T150 motorcycle. I open my spark plug, and i see it's white, I go online and find out that my engine is lack of gasoline and more air (my engine is very hot). I want to adjust the air fit with the gasoline to get a brown color (the best) but my motorcycle is FI engine. So i cannot adjust by mechanism. My friend said that changing the air filter (make it more air come into engine) and then the FI system will adjust the gasoline to fit with the air. Is it right. if not can you tell me some trick to adjust that to get the best color of spark plug. Thank you.