When your battery is dead or so low that you have to jump start it, approx. how many freeway miles does it take to bring it to a full charge----assuming that the battery is in good condition?
I believe you'd have to ride for a few HOURS running the engine above 5K rpm. The charging system is like a trickle charger from what I've heard... little by little.
It's better to buy a charger and put the battery on for a few hours. That way, you're guaranteed a proper and full charge (unless your battery is bad).