Yeah, assuming we are talking a fairly stock machine that used to run good and now doesn't, it sounds like it could have a massive airleak, causing a lean condition. Reeds, compression, and LEAKDOWN TEST.
One more thought: pilot jet. You said you had the carb off but if you couldn't see the jet numbers, then it doesn't sound like you took them out and cleaned them. Remove both the jets and spray through them with carb cleaner. Spray through all the passages too. Before you replace the jets, hold them up to the light and make sure you can see through them. The pilot jet has a tiny hole that is easy to clog.