Hi does anyone know if the speedometers are interchangeable thru the years.
My 1984 k100rs speedo doesn't work . im looking for a 2nd hand one  but wonder if the wiring at the back uses the same connectors

thanks

the late 85 and further on have a different fuel sender and electronics ....
so yes it may fix the speedo ...but you may have to exchange some boards internally to get the fuel warning light to work

hope that helps

The wiring for the 85- and 86+ instrument clusters is identical with the following exceptions:

On the early cluster pins 7 and 8 are brown/white and brown/black for the two fuel level sensors.

On the later clusters pin 7 is white from the newer fuel level sender and 8  is green/yellow for the ABS warning lamp.

On an 85- cluster the warning lamps under the speedo will be red and yellow, On an 86+ ckluster both will be red.

Your level of K-bike knowledge never fails to impress!

I have done it without issues. Indeed, you'll loose the fuel warning lights, but most only get irritated by the 7 litres one and tape it off. A good day counter works just as well.