I put on my new Thunder Alley pipe saturday.While I was at it decided to drill some holes in the air box.Have a yz450 needle on order but it has not arrived yet.So I changed the main to what was sugjested by TA. a 170 he said to leave pilot alone,I'm using a 48,dropped clip to number 5 pos..Started bike would not run without choke.Right now I have had to go all the way up to a 65 pilot to get it to idle and run pretty good. This is my first 4 stroke so I'm new to jetting them. Are that big of jet changes common ? Would the YZ450 needle kept me from making such a big pilot jet change ? Is anybody else using a TA and opened up airbox? and if so what jets are working out for you?