Speedometer gone mad

[Andyk]

2 days after riding in extreme rain in Wales last week my Speedo has gone erratic. It shows the correct speed intermittently but fluctuates between 90 to 1  mph and everything between. I have cleaned the rotor and pickup but no change. The bike is a 2012AL 2 with 10k miles.

[Rusty Nuts]

Rotor and pickup? What and where have you cleaned, please?

[kwackboy]

ABS Rotor and sensor presumably... 

[Rusty Nuts]

That's what I thought, but isn't the Speedo data taken from the gearbox on that model?

[Rixington43]

The speed sensor is behind the front sprocket cover and reads off the main output shaft using a rotor which bolts on the end outside the front sprocket.
If this is what you've already cleaned then it might be a new sensor assuming the rotor is undamaged. If this isn't what/where you've cleaned then see the downloads section of the site for the service manual for the AL2 which I think is 2012 if I've picked up the codes correctly. The world stopped at K7 for me....

[Gert]

You may have bad ground / earth connection. The connectors above the radiator are a documented failing, after riding in rain, on the L2 Glee.  If your ride has a cover over these connectors, then chances are that they have not become wet.
Also check the wiring harness around the steering stem and have the rear cylinder is not pulling tight to allow the harness to rub through. Some UK Storms have been known to have wiring loom issues, that cause wires in the harness to short or snap off.
Example: https://www.v-strom.co.uk/smf/index.php?topic=34902.0 and https://www.v-strom.co.uk/smf/index.php?topic=16745.0