Let'* say it.
Checking the cables isn't good enough on a bonneville.
You need to remove each cable at each and every end, clean each connection, check under the rubber booties by the battery for more corrosion and only then can you be sure you have done this properly.
Took me about an hour without sweating a drop. Up until I checked under the boots and removed every single connection...I kept having problems.
Bonnevilles want more loving under the hood.. be kind to your bonne..and it'll love you right back.