I have read through everyone's problems with their PWKs. I have a YZ250 with a 41.5 PWK that wouldn't start, was dead down low, idle screw all the way in, pilot screw about quarter to half out. I even tried a new cylinder on it, still wouldn't start. So I started brainstorming. I was on a mission. And I finally figured it out and even found more horsepower while doing it! My YZ now runs a 60 pilot, starts on first kick when warm - second kick when cold and idles perfectly now. Send your carbs to my Performance Tune shop and I will get that PWK working properly for $50. Want even more horsepower? Ask for our Performance Tune Race package for an additional $50. We have our own track that we test/tune on. You could as well if you can get to us. You too will be a PWK fan.