Hi there. The simple answer to your first question is NO. Converting to 12 volt system requires many items to be changed or modified as in, all bulbs, generator and regulator, ignition system, instruments, horns, wiper motor if electric. Starter motor might survive OK on 12 volts. Why would you want to change a good 6 volt system. Just fix whats wrong with it if there is a problem. Give us more information on your project. Regards, Kevin.