Speedo fogging up

[MikeFossl]

Any recommendations?  All it does but rain here on Vancouver Island over the last few weeks.

[Matt Chapter]

I judge my speed based on the screams of other drivers / pedestrians, or the light shift as I ramp up velocity.  Not much time for looking at gauge whizzing around town.  Another tell tale is if there's someone behind you.. probably time to speed up.

Luckily my commute route has easily identifiable gendarmes.

(My speedo is kaput, I just use the tach + the seat of my pants.. I don't actually care about the number of speed as opposed speed vs conditions)

[Barry]

Any recommendations?All it does but rain here on Vancouver Island over the last few weeks.

It's a common enough problem and I'm not sure there is a 100% guaranteed solution. It's the tacho that fogs up on mine.  Last time I dried it out I tried to use some science to get a good result. If you look at dew point vs temperature that means sealing it back up not at a high temperature but in a low temperature low humidity environment.  I threw in a desiccant bag for good measure but that won't help for long unless the enclosure is sealed. I used silicone grease around the lens and bezel joint. So far it's worked pretty well.

Euro speedo's are less of a problem as they don't have the reset button in the lens.

[larstorders]

A good cure for fogged instruments is not one that everyone will be happy with. But it has worked very well for me in England's damp climate.
Using a drill or burr, at high speed, make a hole of 1-1.5 mm in the glass at the 12 oclock position, as close to the metal rim as possible.

[Luca]

Euro speedo's are less of a problem as they don't have the reset button in the lens.

I thought that was a production date factor, not a market one.  The only part of the speedo you can touch on an LS is the face... and I thought it was the same for the R80 G/S, which is why they changed the general design with the introduction of those bikes.

When I repaired my LS's odo/trip meter I replaced the reset button boot, which was the cause of water intrusion.  It's seen plenty of rain since the overhaul without any fogging or modifications.  The bezel seal was put back dry.

Other than the trip reset the possibilities are either a bezel seal that's leaking or perhaps (at a long shot) the light bulb holder is allowing lots of moist air in.  A hotter bulb will help evaporate accumulated moisture.

P.S.  It's probably a good idea to have a look at the speedo cable and look for rusting.  If the gauge were to get enough water in it, it could run down the cable sheath and dump into the transmission.

[Barry]

Euro speedo's are less of a problem as they don't have the reset button in the lens.

I thought that was a production date factor,

Luca,

You may well be correct. I just hadn't seen a Euro model with the button in the glass and they are not shown in the parts fiche. I've got to admit I made an assumption that it was the sort of dumb idea the marketing people came up with to provide the convenience of having the rest button more accessible at the potential expense of weather proofing and that they thought some markets would demand it and others wouldn't.

I've just found this which suggests it was a feature from 81 although they seem to have titled the page as a tachometer when it's a speedo. Potentially a very useful diagram and it's not a bad quality image if you save it and zoom in.

I still think compromising weather proofing is a dumb idea though.

[Lucky_Lou]

Mine has the trip reset underneath (79) never had an issue with the speedo fogging up but the tacho as always done it.
Lou

[Bob_Roller]

My speedometer has fogged up every time I wash the bike .
I don't wash the bike any more than I have to, once a year presently  !!!

[tvrla]

As far as I know, the reset button was on the bottom till 1981. After that they came out the lens. If the rubber cover isn't dried out or cracked, water won't enter.

As for fogging - it is something of a hopeless cause. Sealing them up doesn't necessarily work, and most of them are open to atmosphere on the bottom - speaking of airhead gauges from 1970 to 95. The Motometer gauges came both ways - sealed and open, and they could all have fogging issues.

It rains a lot here in Portland Oregon, so you know I've had my go-round with my own bikes. I've had the idea the illumination bulbs draw moisture from the air when they cool, like mufflers, so have had some success using LEDs. Better, but not totally fixed.

Do make sure water isn't getting in around the lens. A puddle inside doesn't help.

[Ed Miller]

My Trailtech Vapor doesn't fog up....

[montmil]

My Trailtech Vapor doesn't fog up...

Yep, what Ed says. All three of my Airheads have digital instrumentation. I never was able to correct the occasional fogging inside the tachometer. Never had the issue with the speedo.

[larstorders]

Gortex fabric is used to combat fogging in some instruments and is reported to be effective, unfortunately I can't remember which ones. Anyhow, a gortex 'diaphragm' beneath the rear instrument cover, for instance,  allows 'breathing'  (possibly helped by a few breathing holes) and an exit for the water vapour so there's less of it to condense on the cooler glass face. Should be easy to fix up something like this.

[rev_mook]

My speedo has fogged up too.  Normally it doesn't rain in Southern California, and when it does the bike sometimes goes inside.  Last time it rained (which was not nearly enough to help our drought) the bike was outside.  

In the past when this happens the fog clears up after a day or two of being in the sun.  It's been a few weeks now, and it still has not cleared up.  This prompted me to remove the instrument from the bike.  Upon inversion, I was able to dump a suppressing amount of water out from the illumination bulb hole.  I left the speedo in the sun for 3 more days and it's still foggy.

I think this thing needs to get opened up to air out.  I figured the black trim ring around the face was threaded, but it seems like it is crimped on.  Can anyone confirm this?  What is the best way to open one of these assemblies?

~M

[Barry]

It's crimped on.

You can carefully un-crimp it by working around the the back edge with a screw driver but some distortion of the bezel is inevitable. Perhaps not the end of the world as on our bikes as much of the bezel is hidden. One method would be to support the bezel during the un-crimping process. Cut a hole in a piece of wood the exact same size as the bezel (easier said than done) If the speedo is a fairly tight fit in the hole it will contain some of the distortion.  Maybe it could also be supported by using some sort of large hose clip but I've never tried it.

[marxbrew]

OK, weird idea, but maybe....

Since you've got it off anyway, maybe try the old trick for wet cell phones.... carefully put the whole speedo into a big bag of uncooked white rice and seal it up, like in a big ziploc. Let it sit for a few days... The idea is that the rice will absorb the water and dry things out. Sounds crazy, but...

If it works for you, let me know... My tacho is perma-foggy, and I've been thinking of trying that rice bit myself..