Speed Sensors

Speed Sensors … do they really sense speed?

Bullocks, of course not. What they do is counting pulses. Just that. It's the speedo motherboard that converts the numbers of pulses into readably speed. Some speed sensors aren't even connected to a speedo but to the engine ECU that does the conversion job. The speedo reads the speed that it indicates from a data stream it gets transmitted by the ECU. The latter system is found in 2004 and up Harleys.

How do I find the right speed sensor?

For the original replacement sensors, please refer to the model assignment and the Harley-Davidson spare part numbers. We list both with the respective sensor under facts. The installation is then very simple: disconnect the old connector, replace the sensor and connect the new connector. These sensors do not need to be adjusted, the calibration is defined in the speedometer instrument.

If you do not have an original speedometer, you may also not have an original speed sensor. If the speedometer sensor has only two connection cables, it usually is a reed sensor. Reed sensors (or also called reed switches) are actuated by a magnet and do not need a supply voltage. One of the two cables is connected to the tachometer input, the other to minus.

In the sensors with three connection cables, there are three connections: Power supply, speed signal and minus. Our Daytona and MMB sensors need 12 V power from a battery. Battery-less 12 V electrics are not suitable for sensor operation.