Does the fuel screw affect from no throttle to 1/2 opening? I am getting some popping after letting off the throttle in race situations, will the fuel screw allow me to richen it up and get rid of the lean / popping, and by the way 2000 wr400 all stock, except lid off, baffle out, and stop ground down. And I checked all the connections between head, head pipe, and muffler, no leaks. And yes its true I am still alive, I've been lurking and riding my new KTM Adventure R. Thanks in advance P.S. you can join the Blue Ribbon Coalition on line, I just did. Have you, protect your right to ride.