My son's first bike was a Honda 100cc street bike. It drove me absolutely nuts intermittently refusing to start. After way too much time, effort, and expense, I found a stripped wire that led to the points that was intermittently shorting out to the cover over the points. On more than one occasion I was ready to throw the bike away and buy him a new one, but I finally found the bad wire.
Might not have anything at all to do with your problem, but 1/4 inch of black electrical tape made my life much better.
Tom in TN