It's an old thread, but here goes. When revving it freely the needle sometimes remains up, so at iddle it would show 4k, 6k or something random. It seems like the needle is a bit loose.

I took the headlight and the plastics down in an atempt to open the dash, but I'm stuck as I need a super small star type key for it. Will go and buy a set and try again this evening, but meanwhile if anybody has done this, drop some winsdom upon us