OK, will '12-volt' coils (standard early 70's points-type ignition) work on a 6-volt bike?
I once had a Honda CM185 Twinstar, and it was a 6-volt bike and some previous owner installed a 12-volt battery. Popped all the lights (which is how I got it for free!), but the bike ran just fine. I replaced all the bulbs with 12-volt bulbs from junkyards and it was months later before I even realized that it wasn't originally a 12-volt bike. Put over 10K miles on it just fine.
But what if, say, I have an early 70's Honda SL125 (6-volt) and I try to use a 12-volt coil off some other bike, say, the Yamaha 650 coils Bill bought and used on his 450?
It seems to me they should work fine (although maybe not 100% up to the design engineer's specs). I mean, the current flows thru the coil thru the points just the same and when the points open, the plug should spark just the same, no?
Thoughts? Any first-hand experience?