Speedometer problem

Hi peeps, took my '07 990 out for a blast today, not as far or as long as I wanted as the speedo reading would only show intermittently. Sensor cable looks fine, could the pickup be playing up? No other dash/light issues, anybody else had this?
Thx

Yep, my sensor just simply stopped working - simple to replace.

Might just be crud on the disc bolt heads though.

Cheers 47, gives me a start on problem