Moped Army

Hi
I sort of have the same problem as dan, but my moped isnt modified to the extent of his. I have a birturbo pipe, and a 27 tooth speed sprocket. My moped dosent like running at low rpms, and dies out. When I get it running it dosent hit its usuall top speed. It does run though. I tried cleaning the carbeurator, but that didnt seem to help, although I suspect it as the culprit. What could be wrong with the carb. When you answer me, you are going to say its running too lean(more air, less fuel) or rich(less air, more fuel). I dont know how exactly I can adjust this, or to know which it is running. I have a 2001 Tomos Targa LX. Also dosent exellerate as fast as usuall. gets fine spark, and spark plug is good, everything mechanically, electrically is good, just carbeuration is wrong. help me out here, want to ride!
it has a delorto or whatever carb with a #53 jet