magneto retard lever

The R68/R69 BMW motorcycle magneto ignition retard lever

by Duane Ausherman

This lever has often been called an advance lever.  That led to a long discussion of what the lever is properly called.  The lever is only used for starting and is not needed for that.  Since it spends nearly all of the time in the advanced position, and when it is used, is retarding the timing, I call it a “retard lever.”

This photo is from an owner’s manual that, from the pictures of the front fender and spokes, would be either a 56 or early 57.  I think it clears up any issue of the purpose of the ignition retard lever.  Excuse my poor lighting on the page, but using a flash reflected badly.

The R68/R69 Bosch magneto for the retard function has a slightly different system for ignition timing.  The points plate for setting the timing is the plate that this lever operates.  It may be impossible to get all of the marks lined up correctly.  Sometimes one must compromise on the timing.

I don’t like this magneto system due to the limited ability to adjust the timing.  If I were restoring to judging quality, I would leave the visible lever in place on the handlebars.  However, I would use a normal magneto or go to an alternate system, such as the Mz.  A Concours d’Elegance judge will only inspect by visual means.

Updated 15 July 2022