new reenforced rev. cables

Are your speedo and tacho reproductions or originals? this looks like a imperial cable square trying to enter a metric square hole.

You can get the opposite of this, a 3mm square cable engaging with a 1/8" speedo g/box drive,

It works for a while until the square bit gets worn and rounded, then no or very erratic speedo reading.

I think a lot of this comes about as to where the cable manufacturers get their components from   

Hi Peter i bought a new speedo cable for my BSA  it only did about 20 mile and stopped working the speedo head had been reconditioned and a new drive had been fitted  the cable looked ok but when measured was slightly smaller square on the ends . i think it depends who is making them as you suggest .

I had exactly this problem with a new Rev counter cable I recently bought from Andover Norton.

I originally thought it was an issue with the Rev counter - some obstruction in place when trying to insert the cable ? I tested the Rev counter with an old cable and it was fine. I had to put the new cable in the vice and lightly filed the four sides whereupon it fitted.

Hope this helps.