Out of curiosity, do you have the Eastern Beaver on it? If not, then it could well be the ignition switch wiring. It is also worth checking the starter button contacts, as well as the clutch and kickstand safety switches. The contacts can get dirty and corrode. They are easy to take apart and clean, but be very careful not to lose the little springs and stuff as they try to exit their cramped quarters with expeditious velocity.
Also check for loose and dirty wiring on the heavy duty cables - both at the battery ends and the starter motor ends.
Some folks use an additional, or a heavier duty ground cable to help starting. There is also a relay mod that adds an extra relay to get power directly from the battery to the starter, rather than through the ignition switch wiring.