Did you clean out all the jets and passages with a good carb cleaner and then blow them clean with compressed air?
Can you please be more specific in regards to "it won't run"...is it surging at idle? Reving up? Just dieing? Does it start hard?
A few basics checks:
Have you changed the plug? What color is the current plug (the tip where it fires: brown, dry and black, wet and black, white?)
Have you adjusted the idle and air mixture screw?
Are all the connections tight on the carb?
Why were you messing with the jetting? The only time you should mess with the jetting is when changing elevations, or you have added aftermarket performance parts that necessitate changing the jetting.
Let me know and hopefully we can get it figured out