Speedo problems

[clyde]

So coming back from IoW in the pouring rain I loose all lights and speedo. Lights fixed and think it was just due to the amount of rain and possibly water ingress into the headset....
Speedo...checked cable by running it with a drill....speedo works so cable ok.
Suspect worm drive but remove it and it looks ok but very greasey. Tried spinning wheel to see if it spins and the answer is no so looks like its hub apart and new drive worm.....
Am i missing anything.

Cheers

[MK Monty]

You say the speedo turns with a drill. Next is the bottom end. You say the worm drive is ok is that a steel type or a plastic one. The steel ones can damage the nylon inner worm drive but they will normally turn and stop turn and stop. Stick a nail or something on the speedo drive and spin the wheel put a bit of preasure on the nail to see if it stops. Also try and pull the drive out a bit I have had to fit small packing out washers on the back end of the drive to get it to mesh correctly. Last the inner nylon worm drive may be damaged or split and come off the hub. Again these are available in nylon or metal. I’m sure one is designed to be sacrificial. Steel on steel is not a good idea. Once you get it spinning you may need to shorten the outer cable to get the square cable drive to fit further into its socket

[clyde]

Yes speedo turns with a drill on the cable so that ends ok.
Removed the worm and its a nylon one on a steel shaft. It dosent look damaged or worn.
Im suspecting the inner worm might have come adrift or broke. I noticed on the way to the IoW the milage seemed abit off.

I will order both worms as they arent exactly expensive...thanks for the suggestions MK Monty.
It worked prior to this so dont suspect the cable will need shortening etc.
Thanks again.