Last night I YZ timed my WR400F and started it today (well barely). I also raised the jet needle one clip putting it to the center position (it seemed to be a bit lean on quick throttle application during my last ride). At any rate when I started the WR today the jetting seemed way too rich. It smoked black smoke when revving quickly and didn't want to idle very well. Overall it just appeared to be running too rich. I currently am running: The stock pilot (45) with two turns out. 175 main jet (168) stock Stock needle in Center position White Brothers E Series pipe with spark arrestor insert and 5 plates White Brothers header (but dented a bit by previous owner) Air box snorkel removed but top lid still on Temp today when running around 45 degrees at about 450 ft above sea level, foggy with high humidity. I took the time to put the bike back to WR timing (just to make sure I didn't mess anything up) and it ran fine a bit richer from the needle setting but nothing at all like it was with the YZ timing. It idled perfectly fine! So my question is whether the YZ timing effects jetting? Also, while I'm at it do you loose any bottom end by going to the YZ timing? Thanks in advance!