Morris MM74L Magneto for Alternator Big Twin Harley Davidsons 1970 – 1973 When building a chopper, custom, or bobber you want to keep everything tight and minimal as possible. A magneto allows you to run your bike without a battery, eliminating a ton of extra wiring and components. The Morris Morris MM74L Magneto features an auto advance, and manual retard for easy starting. Comes standard with a black magneto cap. No returns are accepted on magnetos as they are made-to-order.