Speedo/Tacho damper fluid

Can anyone tell me what fluid to use in the needle damper of Nippon Denso speedo and tachos.  Thanks

A good start is 100K CST silicone differential fluid. If You want a slower return to Zero try 200K. Note Tachs and Speedos have different drive units and spacing between mechanisms. Same for Seiki.

Silicone oil/grease seems like the right type of fluid, but I was curious if you could find silicone oil specifically made for damping.  

A quick google search turned up two uses that seems pretty common.  Damping fluid made for turntable tonearms, and damping fluid made for RC car shock absorbers.  

It seems likely that the tonearm damping fluid could be a good place to start. 

Also, this place has a range of viscosities.   www.clearcoproducts.com/silicone-damping-fluids/

DOHC, that's exactly what i've been using for 15+yrs doing these gauges. You want a "tacky" fluid, NOT oil. I use a product called "Factory Team", in different viscosities. Actually rumor has it a subdivision of Lucus Oils. I'd never thought of record player fluid but i'd bet it's similar. Probably the same fluid used in multiple things that you'd want damping.