Speedo drives

[Perkin]

No, not travelling to the pool already in the correct attire, but the small nylon helical spur gear on the end of the speedometer cable. Specifically, my speedometer cable.

When I bought the machine the drive was already knackered, ground away in time-honoured fashion, but the owner hinted that it had happened before, and there's less than 10 miles on the speedo (which suggests it hasn't worked since it was imported in 2017).

Should the drive gears always be replaced as a matched pair? Are they colour coded, or do I have to count the teeth to know what I need to buy? The current one has 11t. It's a 150 Standard (VBB2T) but has been converted to 10" wheels so the gear on the hub probably doesn't match the cable gear. There's no excessive drag in the cable or speedo, although the cable does look slightly long.

Thanks!

[allvespa]

I have been searching for a driven pinion for my 1966 Allstate Vespa Crusaire. The scooter ID numbers indicate it's a Primavera but the pinions I've received for Primaveras are 8 teeth and red. My old pinion color is green and it has 9 teeth. I have been looking and searching on and off for two weeks and have been unsuccessful in finding a suitable replacement. However, I have noticed some things that may be helpful to other owners. There is more than one gear pitch used! Regardless of the number of teeth or the gear color, the gear pattern for the drive pinion and driven pinion absolutely must match or the metal drive pinion will just grind up the driven plastic pinion. If any owners are having destroyed plastic pinions, I suggest the problem may be the gear pitch and helical angle for the two gears may be different. Look carefully at the two gears; the curve, spacing and profile of the teeth should be identical. If not don't even try to install the plastic pinion no matter what color, diameter or number of teeth it has, it will just be destroyed. If unable to find the correct pinion, the only safe way is to purchase a matched set with the number of teeth as close to the original as possible. Never use two metal gears unless you're absolutely certain they match. A cracked housing, shaft and gear damage will result!