Speedo in pieces
Posted: Fri Feb 20, 2026 5:23 pm
Thanks to Clay, I have a spare speedo to play with. The plan is to swap a gps mechanism into it, but to keep the original pie graph style readout. I'm not sure how that is going to go, but thought that it might be of interest to pull it apart and see what's going on.
Instead of a needle, the speedo has a plastic disc mounted on the motor spindle. The non-moving backing plate has orange painted on part of it, so that once the disc gets past about 40mph, the backing plate orange is showing as a black painted section on the disc moves past it and then as you further increase speed, the disc orange segment keeps moving past so that what you see as a readout is made up of both the static backing plate and the orange on the disc.
The oddometer drive shaft runs off a gear on the motor and connects with the mile counter wheels. This needs lubricating with white grease or similar.
The cable drive shaft has the bronze bush on the end that needs a clean with brake cleaner or similar solvent and then a dose of light oil- sowing machine oil is the right viscocity for that job.
Instead of a needle, the speedo has a plastic disc mounted on the motor spindle. The non-moving backing plate has orange painted on part of it, so that once the disc gets past about 40mph, the backing plate orange is showing as a black painted section on the disc moves past it and then as you further increase speed, the disc orange segment keeps moving past so that what you see as a readout is made up of both the static backing plate and the orange on the disc.
The oddometer drive shaft runs off a gear on the motor and connects with the mile counter wheels. This needs lubricating with white grease or similar.
The cable drive shaft has the bronze bush on the end that needs a clean with brake cleaner or similar solvent and then a dose of light oil- sowing machine oil is the right viscocity for that job.
