speedo needle jumping

[Timbollew]

Yeah it was the sensor knackered for me. Under the tank you'll see a white connector with three wires white red and black is my memory serves me. Best way I can describe it is triangular with rounded edges. Or you can just trace the wire back from the left side (sitting on bike) of the front wheel. It runs along side the brake hose. Check this cable for wear as they do wear through, but may well be the sensor. Mine stopped working completley eventually.