speedo not working

This my second effort. Can't get speedo to register. Rebuilt speedo from Nisonger. Know it works , Put a drill in reverse on it. Right ratio gearbx on wheel. Been told I can't have a chronometic speedo on my 73 Commando. But I do according to your diagram on your site. Had the bike for 40 years. New speedo cable. I feel the inner cable is to short. From Walridge in Canada. Mine is 71 inches end to end with 7/16 into the speedo. I think I need 70 1/2. Longer into gearbox. any sugestions? Anyone able to give me a different length?

I have a chronometric. It uses 1/8 inch square drive with 1/2 inch into the speedo. I see no reason why 7/16" into speedo would not work.

Suggestion: Remove cable at the chronometric. Spin rear wheel and observe: is inner cable turning? If yes, try holding inner cable with the fingers while someone else turns rear wheel. Inner cable still turning? If yes, problem is at speedo end: drive size right?
If no, problem is at drive end. Excessively worn ring and/or worm in speedo gearbox could be the problem.

Hope this helps.

Slick

"Been told I can't have a chronometic speedo on my 73 Commando. But I do according to your diagram on your site."

Are you sure it's not magnetic? If there is a green globe or green dot then it's magnetic, not chronometric.