speedo worm drive

[disco2hse]

I think that would be the right approach. It is likely there is nothing mechanically wrong, but that the magnets in the speedo have lost their oomph. It might also be that someone has replaced parts the gearbox and changed its ratio. Anyway, mine was reading the same amount out, yet the odometer was accurate, therefore the problem was with the speedo and not mechanical. This is apparently the most common issue with speedos of that age and earlier.

Not a big deal to change, but watching it done is truly fascinating.