i have a full yoshi system,open air box & a k&n filter
i am currently running 160/165 mains,25 pilots,needle on 4th clip (yamaha jet kit)
icant get rid of hesistation or stumble + stall at low rpms
what jetting should i be running at sea level (sac,ca) ??????????????????

 

You might have to bump your pilots to a 27 and 3 turns out

 

Try your needles on the 3rd groove and 2 to 2 1/4 on the idle screws.

 

I agree with sixsixT. I have used the exact combo of settings he recommended and they worked well. Assuming you are talking about having the needles on the 4th clip from the TOP, first try adjusting the front fuel mixture screw (idle mixture screw) in or out to see if that helps. If not, then raise the needle clip to the 3rd position. If that doesn't help, Put everything back to where it was and go up one size on the pilot jets. Good luck!

RR1