Ok guys so my last thread kinda died out so decided to start hopefully one last thread to account for my couple questions. Please guys if you know a thing or two about this stuff just chime in or if you have a 400ex then yeah help a kid out lol… Anyway so just wondering what you guys think of this jetting set up: 2002 400ex all stock except a current K&N filter with precharger (prefilter) airbox lid on, stock exhaust. had stock 148 and 38 jets in it from previous owner (he ran it with the K&N and stock jetting i presume) I ordered a Genuine Keihin 152 and 155 Main, as well as a 42 Pilot. What do you guys think?