There's a three cyl. Suzuki model from the late 70's into the 80's or so that has a tach cable you can use. I can never remember the model when I need to but how many can there be, right? It will probably be a bit longer than what you need, but the cable lets you bend it around pretty good without binding internally. I moved my speedo to the handle bars when I changed my tank and it works great.

You can figure out the model and see if you can order a new one - OR . . . I got my cable at a bike bone yard. I told the guy who "knows" the yard my problem and he said "I think I know what you need". Took me on the golf cart through the mud to the bike out in the rain and loaned me the pliers to take it off. Can't do any better than that.

Jack