250-500cc WR 250 jetting

OK i need some help 2006 wr250 i have been racing it off and on for a year now .New motor and reeds but ever since i got it both before and after the rebuild here is what happens
Down low runs perfect never a problem
crack the throdle never a bog never load up will start to pull hard
BUT get on it hard from 3rd gear thru to 5th it spuders as if it is loaded up then after a while it clears up Will also foul spark plugs about every 100 miles or so My CR 125 will never foul a plug
So i took the carb apart to see what is inside
Mikuni with a 3.0 slide 180 or is it 380 main
35 pilot air screw 1.5 out
needel is different then any needle i have ever seen says YA 59 clip in #2 i have tryed all the way to the top same thing
has a real different taper then all the other needel i have seen
straight leaded race gas 110 mixed 40 to 1 stock gearing ridiun plug br8eix
i live at sea level and race up to about 3,000 feet
With a new plug and ride it hard it can win but take it easy and it will run bad and foul a plug

Thanks for the response have you ever seen a needle with a ya 59 on it might be ya-50 hard to read

Ajaxauto,

It is a 59. They come with a 61 or 62 stock I believe but it has been a while. I guess I could just go out and check in the two I have sitting collecting dust. Whichever it is I have several needles that will work on both sides of stock if you want them. PM me.