The issue I'm having at the moment is that the rev counter is working but the speedo isn't. I've tried two different sets of clocks. Any suggestions?

check the cable and the drive

Tacho is electrical, whereas the speedo is mechanical. Check the plastic drive between the cable housing and front sprocket - it is very common for these to round off. If it has, check the drive and the cable to ensure they are free from shite before replacing it as they round easy with resistance from bunged up cable or drive.

They can also get forced too far onto the tab that protrudes from the cable drive mechanism, and be pushed away from the sprocket. A couple of washers behind it sorted that for me.

Cheers guys, I'll have a look in the morning!

Hey, im having the same problem.
Ive checked all of the above and its a new cable.
Anything else that could cause this?

NOt sure what u mean Speedy