True confessions here! Working on a '78 standard model that overall seemed in good condition. Decided to add a second disc to it as I had most of the bits. So, in the process of re-assembling the front end and installing the speedometer drive unit on the wheel, I discovered that the end of the cable had been twisted right off inside the unit. Attempts to remove the broken-off end all failed. But, they are inexpensive on "that site" second-hand, so I went that way (time expedient you know!). Got a decent second-hand one, cleaned it and lubed it up, new cable, and, as the Brits say: " Bob's yer uncle"! Not quite. First spin around the block and, hey, no speedometer! Whazup?? Pulling off the end of the (new) cable from the speedo drive shows that the end of the cable has twisted right off in the drive. Hmmmm.... I've been here before. And then, the light bulb goes off! Checking up at the meter demonstrates that that sucker is locked up tight, which meant that end of the cable was held in one place while the other end twisted itself off. I happened to have snagged a working second-hand meter earlier this year, so with another cable I will be functional. Just sharing my failure to really assess the situation fully, and think through just why the cable had broken that way. Sometimes I get excited and just want to 'get on with it'. So I'm going to try to slow down a bit, and maybe make better time in the shop. My failures are the only things I think I ever really own!