The AFR # I take it stands for air fuel ratio. Is the number the amount
of air to one part fuel ???

 

yup. mass of air to fuel.

 

So the larger the number the leaner it is? So what numbers are considered best for mileage or power or cooling and still be safe for the engine

 

warning... I'm no gear head... ok.. I guess that would depend on different variables such as whether or not you are running an oil cooler for one thing. Other than that it would depend on engine rpm and throttle postition. When you twist the throttle to get goin you would want a lower AFR (like 13.5 or so) but if you're just scootin along at highway speed you could be up around 14.4 or 14.6. The higher the AFR, the better the mileage, the hotter the bike. The lower the AFR, dimished MPG, but the bike runs cooler. Take a look at a post discussing The Power Commander V. There will probably be a post that shows an AFR table. It'll show different AFR's at different Throttle Positions vs. Different engine RPM's. You can manipulate (increase) the AFR's values to give you better MPG or you can decrease the AFR to give you better cooling or more power. My take on it anyway.

 

Thanks I have seen the AFR charts but know explaination
of what the numbers mean. I need a simple understanding
of what and why I am changing and how it effects the engine