jetting needles

[lodown]

What is needle Y151 for? I pulled them out when i was changing the clip position. I have some 5N7 that i'm going to put back in. What is the differance between the two? could this be my cause of mid throtle problems, the engine seems to break up when its between 1/4 to 3/4 open?

[sleeper06]

5n7 is a stock needle,is the other longer or diff taper,just read your mods,put the stock needle in in the richest postion,I had the same set-up on a few bikes ,those pipes liked 30 pilots ,needles all the way rich,2 turns out at sea level,+4 timing,

[lodown]

Thanks i will give that a try.