Magneto ignition

Magneto ignitions are among the relics that were once part of motorcycle electrical components.

Componentes do arranque platinado da mobilete Puch Maxi Motovi.

Magneto starters are almost non-existent anymore, except on old motorcycles that have been or are being restored (e.g., Honda CB 200). This is because this component emerged to overcome the inefficiency of battery recharge systems between the 1960s and 1970s and were later replaced by more modern and more efficient ignition systems.

This type of starter works as follows, the plate that rotates internally to the magnet, contains two coils screwed to it. These coils are covered by copper wires and when they rotate, they generate energy by electromagnetic induction (the internal walls of the magnet are covered by magnetic plates). This energy is stored in the capacitor, which, in turn, transfers it to the contact breaker assembly at the moment of the "spark" (which will later be used for the internal combustion of the engine, moving the cylinder piston). The "spark" is generated when the contact breaker points are brought together during the plate rotation.

The big disadvantages of the magneto starter were: its poor ability to provide the "spark" when at low rpm, required space (which is greater than in modern systems), and rather complex maintenance (at least more than in modern systems). These disadvantages were the main reasons for withdrawing this component from the market.

At the garage

We found a magneto starter of a Puch Maxi Motovi, a moped from the 70s-80s in almost perfect condition in the garage. See its assembly in the Mechaniclapse video.

References

Dan's Motorcycle Repair Web Page. Flywheel Magneto Timing. Disponível em: <http://www.dansmc.com/magneto1.htm> Acesso em: 02/11/2022.

Zimmerman, M. (2016): The essential guide to motorcycle maintenance: Tips & techniques to keep your motorcycle in top condition. Motorbooks, Minneapolis, EUA. [Link]