I have a 1981 CT 70 that has no spark. This was running 5 years ago prior to me deciding to break it down and refurb. It is now back together but no spark. I did not do any engine work to it. Thinking maybe mess of wiring behind headlight might be incorrect. Can not find a wiring diagram that matches my 4-wire ignition key switch. Ignition coil ohms out correct. Should there be 6v at the coil when key is turned on? How do I know what K model mine is? Very confused!!!