carb bikes do not have a tip over sensor. its prob. flooded and you are going to have to air it out, an easy trick is to wire tie the throttle open so the butterflys in the carbs stay open, let it sit for a day and re start.
or crack it wide open with the petcock off and crank it for a while, the down side to that is the starter will over heat after a few tries and you will eventially run the battery down.