Topic: Speedometer troubleshooting....where to start?

[zoo mob]

1970 750 K0, speedo lights up, but thats about it. Checked to make sure it was attached at the rear, and it was where to go from here?

[mcpuffett]

you could take off your speedo cable and make sure your speedo drive is working first, if thats ok then attach your cable and make sure thats working ok, if thats ok then your problem is in the gearing in the speedo itself, i have'nt taken one apart so i can't help you further but i'm sure others can  , cheers Mick.

[750fromhell]

My speedo had my needle jumping all over. Here's what I did :

I removed the attachment of the speedo cable to the front wheel. On the cable end there's a groove that looks like a flat screew. I grabed a drill with a flat screewdriver end, connected it to the cable end and ran the drill. My speedo was still jumpy.

I removed my speedo from the bike. I removed the speedo cable from the speedo. I shoved a corresponding size phillips screewdriver tip inside the speedo where the cable used to connect. I ran the drill, my speedo needle was still jumping.

I put my speedo appart as per this link:
http://www.salocal.com/sohc/tech/speedo/spedo1.htm

Turned out I had oil on the magnet so I cleaned it. Putting it back toghether the magnet/faceplate/needle assembly and moving the needle, I eard the magnet binding on the needle housing. I inserted a thin piece of wood on the top of the magnet housing so the magnet would move freely again.

That did it, my speedo works now. It's just reading about 10 mph fast at 70 mph.

... hope that helps.