@Paul Kallus - No, no, no! I was just curious. Albeit anything could be possible...would be interesting if the applied ribbon isn't lined up though??? I was curious for my own purposes. Something you also might want to look at...make sure the bottom of the tach harness is not dragging on the circuit board. I'll email you a link to some MTH documentation shortly. I'm leaning more toward gearing, etc...now myself.
Your issue made me think of setting up a gantry for measuring engine speed along a straight run. Simple enough to set-up but a time eater for sure.
Anthony