Hey everyone. I am replacing the sealed restrictive stock muffler on my australian 2000 wr 400 with a lovely new bills pipe. I need a bit of guidance with what my jetting requirements might change to, going to an open muffler. I followed taffy's advice when I was jetting it for the stock pipe and he was pretty much spot on. I am running a- 42 pilot 75 paj 160 main 200maj obeln pos 2 or 3 wr timing, airbox lid off and bk modded. Always starts 1-2 kicks, never a hint of backfiring, plug fouling or any type of misbehaviour. In my opinion I will probably need go up to a 45 pilot and a 165/168 main when I fit the pipe(tomorrow). Can one of you jetting gurus confirm this? Will I need to richen up even more than this? Should I go back to the stock obdrq needle?(doubt it) Should I just see how it goes with the current jetting first? I would like to be "in the ballpark" pretty much from the start if possible and would really appreciate any feedback I could get from you jetting gurus out there. I've read the jetting Q,s post and this is what leads me to believe I will need to richen up a bit with my new pipe. thanks in advance for any feedback.