The BMW /2 Motorcycle Ignition Switch Diagram Guide

The following diagrams shows the function of The BMW /2 Motorcycle (BMW motorcycle /2 cylinder heads) ignition switch. The diagram may guide you in pushing the key into the switch connects the battery (and generator) power to the horn, stoplight switch, charge and neutral lights, and also breaks the ground of the magneto (device which build up the charge of the ignition system).

Ignition Off
30/51: V+ from generator & battery
15/54: To horn, stoplight switch, and charge & neutral lights
2:   To magneto
31: To ground via generator
56: To headlight and speedo lights
58: To taillight

Ignition ON, Lights OFF

The switch has been pushed in, making contact between 30/51 and 15/54, and breaking contact between 2 and 31.

Ignition ON, Lights ON
The switch has been turned to the right, making contact between 30/51 and 56 and 58.

Turn The BMW /2 Motorcycle switch to the right connects power to the head light, speedo lights and the tail light and when it turned to the left connects power to the taillight only (source: snafu.org)