Saturday
Trying to get my speedo to work after a layoff, I checked the resistance of the sender and got 2.8k Ohms, the same value was available on pins two and three of the speedo connector, so my cleaning of the right side connection was ok.

I was puzzled as I have seen two resistance values in my searches - 2.8k and 280.

• It turns out the 2.8k Ohm resistance value applies to the metal bodied sender fitted to my 1984 K100RS. It bears the number 1 459 013 under the word MotoMeter and has a cross-point screw above the pickup barrel.
  
• 280 Ohm applies to a black plastic version which was probably later.
  
  I checked these personally at a Yorkshire breakers this morning.
  

Hope this is useful to someone


Another update of this speedo saga, Monday

I bought a new boxed blue sheet thing today from Motorworks - sadly when I look at the two together, the new one is different. Seems this one is meant for a later bike. However, having separated the old blue thing from the speedo and tacho I was able to check continuity between the main pins and copper tracks - seems it isn't knackered like I thought. Perhaps it is just the speedo board which has gone.

Looks like I need to speak to them in the morning!

Tuesday
I phoned them this morning and took the afternoon off work to visit them yet again. The blue connector sheet thing was returned for a full refund. I have fitted a new speedo board and I'm back in business! I'll be able to return the used sender I got to try for a refund at the weekend as mine has been eliminated from the enquiry now! Woo Hoo!

Steve

Thank for info.

I beleive you are correct in that the black plastic sensor is for post 86 models with the updated pc boards in the instrument cluster, which is why there are differnt values of resistance for them. i think that they still work but with less accuracy, which may be an issue considering that most of us will at some time have changed the instrument cluster due to age or damage..

Ian

The speedo of my K100RS 1984 was not working when I bought the bike. I dismantled the instrument cluster and found out there are crumb of 3 small gears of the speedo units..(d**m). I managed to get a second hand speedo from eBay and the censor at the same time.

After replacing the speedo unit inside the cluster, the speedo was still NOT working. Then I replaced the censor (used one) and it works till now.

Cheers.

Thanks for posting the info!

OG