So on a 4" flywheel that might be 10 degrees or so. I've read about the advancing mag never really saw just how much advance they provided. How much simpler can a mag ignition be? It would be nice to have it adjustable and offer 20 degrees advance. Contrary to popular belief, the mag parts(Two coils, pickup, and flywheel) from a GT80 weighted 392 grams while the C&H Ignition parts and 4 double A batteries weighted 413 grams, I'm sure other systems vary as the Zenoah engines use a small flywheel. The weight savings is all in the spring starter.