Hello all. I just picked up an 81 KZ750 on Craigslist. I really like the bike but I'm having trouble with the electric start. If I roll the bike down a hill and drop it into first, it starts fine. But when I try to use the electric start, it won't turn over. I've replaced all of the spark plugs and I've fully charged the battery. I'm not really sure what to do next. If the bike starts on a roll, what can I rule out, if anything? I'm really looking forward to working on this bike myself and I don't want to take it into a shop. Any advice?