Here are pictures of my piston after burning 4 gallons of Amsoil through my engine mixed at 32:1 I sucked a cylinder gasket during a ride at Little Sahara. I switched to the Amsoil last year and was getting white plugs so jetted up to get a tan plug and the usual 1200 degrees on the EGT dropped off to 1130-1140` I like to error on the safe side so left it this way ignoring my EGT and relying on the fail safe plug readings, here is my piston from last season I can see now after viewing the underside of the piston that I was in fact on the rich side and the plug readings were wrong, grrr should have trusted the EGT readings (I need a borascope big time), the Amsoil does burn that clean! Note: that is the way the piston came out and was not washed before the picture was taken Below is the bottom of my piston after burning 4 gallons of Golden Spectro with the correct jetting. The flash on the camera makes it look much worse than it really is the scratches you see are not deep and you cant feel them when you drag your finger nail across them. I suspect the buildup on the crown of the piston would have been much less if I had not run the jetting on the rich side.