Hmmm, all sorts of possible causes for it dieing. Could be carbs, fuel filter, fuel lines, could be thermal issue with ignition system, one of the most common being the pickup coils going bad when hot but even that is not that common. How new are the plugs?? Have you inspected the coil secondaries for corrosion and green stuff on the output? When you remove the coil wires cut about 1/4 inch off the end to insure a good connection for the prong on the connector to penetrate the conductive core of the wire, and make sure the rubber o ring is on the plug wire to prevent the wire from vibrating loose.
I would try a strong dose of Seafoam in the gas tank, like 1 can to a full tank of gas and then drive it like ya stole it! Also add some dry gas in case you have moisture in the tank. Wouldn't hurt to drain the carb float bowls and see what kind of crud you may have in your fuel system. I would consider replacing the fuel filter as a "Must do" regardless anyway...