Topic: What's that sensor inside the speedometer (XS400)?

[Raul CB750K1]

Yesterday night I was about to open an XS400 speedometer when I noticed those two wires coming out from it. I had already removed the backlight bulbs, therefore those wires couldn't be used for that.

They were the connection of a reed relay. It was installed in the factory, it is not a homemade mod. The relay sits very close to the spinning magnet of the speedometer, therefore it is there to sense something related with the speedo inner work.

I don't have the XS400, and it was the first time I saw such a thing. Does anybody know what it is for? Does it counts the magnet revolutions? For a moment I thought it would count pulses, in order to -for example- cut the ignition if the revolutions go past a limit, but it is senseless to have it in the speedo, it should be in the tacho.

What is that reed relay for?

[bryanj]

That was one of the first with self cancelling indicators mate, the indicator switch went laft or right and then returned to centre with lights blinking and they turned off with distance or if you pushed the switch inwards

[Raul CB750K1]

That was one of the first with self cancelling indicators mate, the indicator switch went laft or right and then returned to centre with lights blinking and they turned off with distance or if you pushed the switch inwards

I see. The reed relay is giving pulses all the time when the bike is running. If you have either blinker on, say while waiting at a traffic light, it will stay on forever. As soon as you start moving, if the blinkers are on and pulses are coming, the indicators self-cancel. Is that right?

[bryanj]

Yup or you cancel by pushing the switch on the bars in without sliding it left or right