If you have not fitted a known good or new carb, then you cant eliminate the carb as being your problem. But it sounds more ignition related to me, and very possibly something quite simple.
The most common problem on old CDI systems is insulation breaking down in the source coil when the bike gets hot, and OK again when it cools down. Issues with pulse coils are very rare, but problems in either area will generally mean no spark.
I think you either need to think about looking closely at the carb, and if that checks out ok, and crankcase pressure and compression tests are both good, with reeds sealing properly, find and fit an inductive ignition complete.