Sputtering at low rpms

[thunderdork]

I had some after firing issues. So i chamged and gapped my points and cleaned the carbs. No more after fire.

Now my xs idles fine with choke off. But of the start line it starts sputtering until I get up to higher rpms. But if I engage the choke it clears up at the lower rpms, but then dies at idle.

Any suggestions? Next up is probably timing.

 

[Royboy]

It would be useful to know what XS you have and whether or not it has been modified in the carb and ignition departments. Right now we know it has points but that's about it.

roy

 

[CZ650]

Did you figure this out? I have the same issue exactly. Seems like a lean mixture or timing issues but im hesitant to raise my jets again after already moving both up a few steps.