After I restored my CB750 a few years back, the tach & speedo needles were all over the place - unstable. I'd have to sort of interpolate to get a reading. From everything I'd read here I knew that disassembly of the guages was inevitable but couldn't get up the nerve to ruin them. The last time I ordered some OEM parts for various bikes I decided to buy new drive cables for the 750. I always order everything I think I'll ever need to take advantage of the shipping cost I would be paying. Went for a ride today - first non-rainy, non-foggy, non-dreary day in months around here - and after a while noticed that my guage needles were rock-solid. Never expected that. I only replaced the cables because they were looking a bit ratty.
So if you have bouncy needles, maybe new cables will do the trick.
