unsmooth idle

[shibby7]

So I just totally rebuilt a 99 YZ250. I fixed the problem with the leaky crank seal, but now it doesn't want to idle smoothly, or even if at all. It kind of pulses in out. After riding the bike and letting off the throttle it does the same thing for a short period then smooths out and starts it again. I am pretty sure it is just carb tuning problems. On average how many tunrs out should the air screw be from seated? ANy help is much appreciated. Thanks

[MotoMojo17]

check your fuel cable for tears or incorrect routing

[easyas123]

The air screw should be 1 to 1 1/2 turns out from the seated position. If that doesn't do it check the plug to se if it is gas fouled it should be a golden brown color.What size idle jet is in it and check it and it sounds like it may have some garbage in that jet as well.I have a 99 yz 250 and i have to change the main jet during the summer because it loads up during the winter i go back up to 165 vise 162.I run v force2 power reeds ,FMF Fatty, Shorty Silecer and i run 40 to 1 using motul oil and it seems to do well.

[steiner]

sounds to me like it is lean

[dirtdemon4life]

Make sure all your intake connections are secure and tight..Or it can and will be costly to fix..

[yamaha man 69]

your air screw is prob off