The looks of my tach made me sick. What you see is no fog: it's permanent.
Some skilled people have managed to remove the intrument’s bezel by prying the stainless steel ring around it. I looked at the ring and decided not to try it: no way that it would remain waterproof after my surgery. So I cut the plastic open:
Cutting it open with a utility knife was relatively easy. I cut 14 mm (about ½ in) below the ring. I first traced the cut lightly and then over and over with more force until it opened up. I recommend marking a sharp notch across the cut so that you will know how to properly align the bezel afterwards.
CAUTION: there are 3 rubber fingers that hold the back plate in position. You can see the ones at 500RPM and 9500 RPM positions, and there is one at 5100 RPM. If you didn’t read this caution carefully, you will likely have cut through one or two of these rubber fingers, but that’s not a big deal. You can always epoxy them back in place.
After cleaning the inside of the bezel, I epoxied the top on. For an added measure of integrity and water-tightness, I also epoxied a band of fiberglass. Et voilà, c’est tout!
Part II. No more Twinkle-Twinkle
To finish up the job, I had some instrument bulbs to replace: two out of four were burnt up and the remaining ones looked bad. At 57,000 miles, their useful life had clearly been exceeded. The OEM replacement for those 12V 1.7W bulbs is #62142306127, but it's hard to find. A #74 bulb from a common autoparts store will do OK too. But then I wanted to try something better, and I tried these:
This is what they are:
4X White LED for speedometer and tach
Small Wedge Base LED bulb (74 type) 12V~ 2 lumen
3/16 inch wide base, 13/16 inch overall length
Flat tipped LED produces wide beam angle
Replacement for OEM 12V 1.7W 62142306127 bulbs.
1X White LED for clock
BA7s Bayonet Base bulb
12VDC BA7s Single Contact Midget Flange Base bulb with Wide Viewing Angle LED
Replacement for OEM 12V 2W 07119978279 bulb.
Here is a comparison with OEM filament bulbs:
Finally, the completed job looks like this:
If it weren't so cold and wet, I' d go for a night ride.
Hope those bright lights don't night-blind you! (That's probably just some trick photography 
)
My OilHead also had a barely noticeable cloudyness to the tach glass, prolly an aging anti fog film.
