I am continuing restoration on 2 CT70's. The yellow is an H1 and the blue is H2. I have replaced the whole electrical system since everything is 50 years old. I installed OHTOKC electronic ignition, new coil, new battery, new harness. I get a good spark when testing with jumper from OHTOKC ignition plug to ground. A weaker looking spark at sparkplug when using a jumper wire from OHTOKC ignition plug to black coil wire. I have limited abilities with voltmeter but I am learning everyday. Please let me know how to measure the spark and what a good reading would be. Thanks for the help.