A question regarding the tach cable

I just went through the diagnosis of my faulty speedo (it was the speedo itself and is now rebuilt and working fine) and among the many ideas I got from folks on this board was that the drive portion of the speedo cables were in many cases too long on the instrument end and would eventually ruin a speedo. It was prescribed that the speedo drive end of the cable should be no longer than 7/16". Shortly after getting the speedo fixed, my tach quit. Turns out that the lower end of the cable had rounded off so I am replacing the cable. Since I am replacing the cable, my question is, does the recommended maximum 7/16" drive on the instrument end of the cable apply to the tach cabld as it does to the speedo cable?

Yellow_Cad said:

Since I am replacing the cable, my question is, does the recommended maximum 7/16" drive on the instrument end of the cable apply to the tach cabld as it does to the speedo cable?

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Yes.

And on a lot of new BSA speedo cables in the UK the square end is oversize in thickness as well as length, so as well as shortening the square needs thinning. Not sure if it carries over to Norton's as the RGN tacho cable I bought this year fitted with no mods needed and the correct steel cover to heat protect it from the balance pipe if fitted.

Did you use a repro cable or OEM?

Coco said:

Did you use a repro cable or OEM?

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OEM on a BSA ? Have there been any for 35 years ? :shock: (excluding NOS WM20 stuff of course !)

I had the same problem with my tachocable roundingoff.
I solved the problem by repositioning the collar on the wire at the upper end.This allows a "new" portion of the wire to engage at the lower end, and the tacho runs again.

Benton