I am working on my bro's 89' Yamaha warrior quad. It had a horrible bog... so I to the snorkle off, raised the needle 2 positions, and tinkered with the air screw. I have 2 questions... 1) On the warrior, does it have an "air" screw, or a "fuel" screw. In other words, does turning it in make it leaner, out = richer... or the opposite? 2) I have read on here that different parts of the plug read different colors, and thus indicate jetting changes needed. I did a jetting run, wide open in first, pulled clutch, and killed it. The very top of the plug was a dry black, the insides of the plug were a little bit lighter black, and the tip of the plug (im always confused about jetting lingo, but i think its called the electrode... its the metal part that the spark jumps from) was white. What does this mean? Im not too worried about the blackness... it never fouls plugs and has good power. Its the white (electrode?) that im worried about. I know it wont seize or anything since the main jet is plenty big enough, but I still hate to see white on a plug. Any help is appreciated!