Annoying Speedometer Noise at Cluster

I would remove the speedo cable from the head and drive it. if the noise goes away then you have narrowed it down at least. WD40 isn't really a good lube to use on speedo as it wont stop it from whipping in the sheath.
A white lithium or sli-glyde would have been better choices to lube the cable. Remove cable and clean and when sliding it back in coat it liberally as you slide it back in sheath.