Stop light problem

Hello. I have an electric problem on a 50s. When i push the brake (when the stop lights, the engine gets off (till i get my foot up). Might it be a short-circuit? Where should i search for it? On pedal switch?

hi ...


honestly !


i think that it would be the best to go to a mechanic and resolve this problem,

because its very tricky to resolve electric problems virtually on the bulletin board... [:S]

awesome !!!

but if you check the wire diagram, if that you said happens, the light should be always on.

one cable is earth (like frame) and the other is the light's wire. When the pedal is up, these two are connected so the light bulb's voltage is 0. When you press your foot, blue wire gets +6V, so the bulb lights.

if i understood something wrong please explain.


(this is the wire diagram


problem solved. thanks!



i seems your positive wire at the pedal switch  gets in contact with your frame.


check for a good cable and replace the switch in this way- maybe the contact in the switch is bad



I have had this on two 50s's.


If you have a 50s with only 2 coils on the stator plate the ignition coil is earthed through the brake switch. The stop light bulb is in parralel with the brake switch.


Under normal operation the  coil is earthed through the brake switch. When the brake pedal is depressed the earth for the coil is through the stop light bulb. If the stop light bulb is blown the engine will cut out when the brake pedal is operated.


I now have a 40mm m3 bolt with a nut on it in my tool kit that I can put in place of the bulb should it blow while im riding. You can carry a spare bulb but they do get a bit of a hard life rattling around in your tool case.