Hey my buddy went to school at the wyotech school for motorcycles, recent graduated. Kind of had an interesting opinion on what fuel tuners do. He told me that when the manufacturer builds a bike that they have to do an emission test. When they run the emission test they dont check it thru the entire rpm range just a certain rpm for a certain speed and the manufacture sets it to as lean as it can run at this exact rpm. The manufacturer knowing that most will never run at this specific rpm they will never tell the difference. All the tuner is suppose to do is richen up that rpm range. He says that when aftermarket exhaust etc is installed you get a hesitation at a certain part in the rpm range and it doesnt hesitate all the time etc. Just thought this opinion was interesting or if its actually backed up by something.