Tacho moisture.

[Guest bshpilot]

The fine points of mass production . Some just get sealed better than others I guess .

 

but why then is it always the tach ?

ive not heard of anyone mentioning their speedo leak...

 

the tach and the speedo are same manufacture....

[callison]

Just hazarding a guess here, but probably, both tach and speedometer get some moisture intrusion. But, the speedometer had the trip reset stem opening as a vent where the tach doesn't. Since this sounds logical, it's probably incorrect.

[al_roethlisberger]

Since this sounds logical, it's probably incorrect.

 

 

 

 

....true, probably soooo true

 

 

 

 

 

 

P.S.

 

I bet you're right

[Baldini]

why does it only happen when the bikes out running - in the shed it doesn't mist...

[Guest Gary Cheek]

It seems a lot of bikes get it in campgrounds especially after a night time rain . As the sun warms everything in the morning the glass steams up . Sometimes they are fogged all day .

[belfastguzzi]

Surely the condensation is not because of a leak past the glass?

 

I have never seen water sitting in the tacho.

The speedo does not mist up and it is the same glass/seal construction.

[belfastguzzi]

Just hazarding a guess here, but probably, both tach and speedometer get some moisture intrusion. But, the speedometer had the trip reset stem opening as a vent where the tach doesn't. Since this sounds logical, it's probably incorrect.

but as I said earlier, drilling an equivalent hole in the tacho has made absolutely no difference.

[belfastguzzi]

why does it only happen when the bikes out running - in the shed it doesn't mist...

I assume that the glass gets a lot colder (esp. compared to the air inside the clock housing).

[Guest Gary Cheek]

Surely the condensation is not because of a leak past the glass?

 

I have never seen water sitting in the tacho.

The speedo does not mist up and it is the same glass/seal construction.

It has been from what I have seen . The water leaks IN past the glass to rim seal , lies, trapped in the bottom of the housing . The sun comes up ,the water warms and vaporizes. Liquid water goes down , vaporized water goes up. When it gets to the glass it causes the fogging . It can and does indeed occur on both the speedos and tachs . My LAPD Eldo has no tach ,but it has fogged up the morning after getting caught sitting out in the rain .The water sitting in the corner at the bottom of the rim can leak past easily . It is just a matter of the effectiveness of the seal . No matter Tach or Speedo . A very common occurance with many makes .

[Mr. Bean]

Surely the condensation is not because of a leak past the glass?

 

I have never seen water sitting in the tacho.

The speedo does not mist up and it is the same glass/seal construction.

It has been from what I have seen . The water leaks IN past the glass to rim seal , lies, trapped in the bottom of the housing . The sun comes up ,the water warms and vaporizes. Liquid water goes down , vaporized water goes up. When it gets to the glass it causes the fogging . It can and does indeed occur on both the speedos and tachs . My LAPD Eldo has no tach ,but it has fogged up the morning after getting caught sitting out in the rain .The water sitting in the corner at the bottom of the rim can leak past easily . It is just a matter of the effectiveness of the seal . No matter Tach or Speedo . A very common occurance with many makes .

That makes sense. It also might explain why after I drilled my tach housing I have never had the fogging happen again...dispite riding/parking in the rain. Rather than trying to duplicate the odometer reset stem hole, I drilled a 1/4 inch one in the very lowest point on the housing when it is mounted on the bike. This way any water that does get in there simply drips right out. Before I did this, the tach would start fogging up after the insides started warming up. Once the bike cooled back down again...overnight or during work...it would be back to normal.

 

Randy

[Guest Gary Cheek]

Kind of like a terrarium .

Many years ago at age 16 or so I had an MG Midget .The Midget was a good running car except when it was damp outside . After drying the distributor out , on the inside often using a propane torch ,the car ran fine . I tried sealing it many different ways . The old man across the street convinced me to try a pair of holes . He drilled a hole in the distributor bottom and a hole at the highest point on the cap . That was the end of any and all starting problems . It seems water vapors actually came up from the crankcase past the distributor bushes . The vapors would build up ,trapped in the well sealed distributor . Allowing them to escape did the job .

 

BTW ,It's not so much a matter of the glass being cooler as the glass being higher and clear . The moisture collects on the bottom sides of most of the inner surfaces on it's way up . We just see it on the glass.

[belfastguzzi]

Maybe so. I actually drilled the hole at the top, near the bulb, hoping to encourage condensation out (not the side to duplicate the speedo). Perhaps a drain hole at the bottom as well may do the trick.

[Guest rrbasso]

I have it to........

[emason]

'00 V11 Sport - first 3 tachs had no fogging problem, died of something else. Fourth tach fogged the first time I rode it. Removed the nuts that secure it to the housing for a while, didn't help. Still fogs after more than a year, learned to live with it.

Guess I had better find that .25" drill bit.

[Guest aironepony]

I had exactly the same trouble; foggy mindedness.

 

I too have drilled a tiny hole just behind both ears.

 

I still have episodes of foggy mindedness, but less frequently..........er ........er.. ..um....er. Oh b*gger can't remember the rest.

 

 

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