How or can I tell if a gen. is 6V or 12V? Also, can I replace the large groove pulley on my 6V gen. with a small groove pulley? Not sure if the gen. I have with the small pulley is 6V or 12V. I am swapping the 216 for a 235 and the 235 had a 12V coil and I assume a 12V gen. Thanks!