yr vic

the output from your generator is more than twenty volts I know that you might think it would be less but the voltage is governed by a regulator and converted to 6v D C (thats what your battery needs) by a Rectifier if you change the regulator rectifier for one rated at 12 volts thats what you will get. you will need a 12v bat bulbs all round, coil, flasher unit all made for 12v ......... the usual problem with old bikes is bad connections bad earths and a battery that looks like a fossil.