I have never fouled a plug in Australia even when my bike was running very rich and blubbering and running like a dog. (Brand new with over oiled air filter at 1300 metres(4000 feet). Maybe your fuel in the US is the culprit. 2000 WR, YZ timing, 42 pilot, 168 main, Staintune Exhaust with Baffle. DRQ needle 3rd clip, pilot srew 1 3/4 turns. I have been as rich as 45 pilot, 172 main, DRQ 4th clip, pilot screw 2 1/2 turns at 1000 feet and had no fouling. The DRQ is our standard needle and is richer than yours.