2004 yz450f big bore,3k to 8k elevation. 38 pilot jet stock was 42. and 2.5 out on the screw. Well i went and adjusted my rekluse today and while I was putting it back together i noticed something strange! The carburator boot the goes from the head to the carb was split almost in half.WOW you would of thought the bike would be running like crap but it wasn't it was running great.So i stole a new boot off of my other bike (well quad) and installed it on my bike,put everything back together and now the damn thing won't start what the !!! So heres my ???? if the bike was getting more air sucked from after the carb would that be making it leaner? The bike has a 38 pilot jet in it and its been that way for about 2 months running like a champ. i have a 35 to try. I can get it to run for about 1.5 seconds and it dies.I've tried turning the screw up/down, i've tried tuning the idle up,So my spot on jetting was probably all done with a leaking boot. What do you guys think i should do now.More air after the carb would make it leaner i would think so maybe ill try the 35 jet and see if i can get it running??? Any help would be appreciated!!!