ok apparently noone has tried. So maybe i'll be the first. Midlife, do you have any writeup on the speedo anywhere? It is after all electro/mechanical. If not do you have any description of the speedo itself? Like what the end of the speedo cable actually does? From my understanding it is squared to make a specific current that the "speedcup" (i guess thats the metal around the insertion point) picks up on on thats what drives the actual needle. If I'm correct in all of that awesome and I could make it work from there. If not what am I missing in the operation?