If you look at the housing where the cable connects to the speedo there will be an indentation. It's usually on the side or the top of the housing. If you look closely there will be an opening at the bottom that has what looks like cotton packing behind the opening. That indention is where you put light weight oil (sewing machine oil works well), which will soak into the packing and lubricate the areas that need lubricated as the speedo turns. It needs to be lubricated periodically.

Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.