Wide bands aren't cheap or all that easy to install/use and ecspecially tricky without the aid of a dyno or some way to load the engine while stationary. You can get off base pretty easily with all the equipment in the world at your disposal, knowledge and experience makes the difference. PS: another vote for leaving the plug alone with the exception of leaded race fuel or methanol (i'm wasting my time with methanol I never have figured out how to read that stuff! LOL) your wasting time trying to read plugs with pump gas or most no-leads. If your on pump gas and the plug is tan your bike is so rediculously FAT it shouldn't be able to pull a sick whore off a toilet. I plugged an air filter at the MX track a few weeks back and my bike was a little fat anyway, just for kicks I pulled the plug and low and behold she was bleach white! I'm talking about a bike that wouldn't hardly pull third gear to the limiter! Thats a fat mixture.