Are you getting fuel in the carb? if you have a stock carb it will have a sight glass on it, fuel should be seen halfway. When you press the accelerator without the air cleaner can you see fuel squirt into carb? you rebuilt the carb even that can loosen debris in the fuel system and block small passages. You first have to verify your carb is getting sufficient fuel. Like gimpy said check cut of solenoid, when turning key to "ON" position you should here an audible click coming from the carb. I would check the carb before any timing work.
Edit. does your fuel pump work.
Edit. does your fuel pump work.