For years both my bikes had suffered with condensation in the speedo housings. I had tried sealing them completely, drilling little holes, big holes, holes covered with Goretex and the final unsuccessful attempt was to cut two, inch and a half diameter holes in the base plate, and cover them with Goretex. And they still misted up.

So, I asked myself the question 'how do we get rid of condensation in other situations?' Visors...... we open them to promote air flow. Shower rooms.........we use a fan to promote air flow. Windscreens..........others (not me!) switch on their fans to promote air flow. Get the idea?

Well, I sourced a small cooling fan from Maplin (A26GU).....25mmx 25mm x 10mm. It has three wires, red +ve, black -ve, and yellow, which is for speed control and not required in our case.



Then I mounted it into the back plate, wiring it across one of the illumination bulbs, and added a grille to the opposite side.



Yes, I know my mountings are a bit elaborate, but, as mentioned above, I had two big holes to start with and I found two plastic escutcheons which seemed to be made for the job. It could be done much simpler.

And, whoopee! no more misting.

So, if you are frustrated with condensation problems, give it a try. The fan I used costs less than a fiver so it won't break the bank.

Paul.

Great idea and it's a neat setup.

Would you need a filter of sorts covering the fan to keep out the dust/dirt?

Excellent idea Paul.

I have to check the fan on laptops (I don't remember if they are 5 or 12v). They are really tiny and move a lot of air (maybe too much).

Here is a question: are your fan turning in the same sens of rotation or they are oposite to each others?

You can push air in, pull air out or have a circulation (one in, one out).

Which way did you wire it?

CF

blakey

As the fan is drawing air from the gap between the back plate and the alloy bottom casing I've not had a problem with dirt getting in, but we don't have any deserts here, so maybe a fine filter may be needed in such conditions.

Mild panic there, CF.......a post from 'Admin'.....have I been censored or something?....

Seriously though, my fan is a typical computer cooling fan and there was the option of 5v or 12v, the 5v one being only 17 x 17 x 8mm but that would require some extra circuitry.

There is only one fan, drawing air in on the right of my photograph, the air exiting through the grille on the left.

I wired it into the back of a bulb holder; the back plate, fan and bulb holder can then be easily seperated for getting at the rest of the gubbins.

Paul.

Very neat and ingenious Paul! Those escutcheon plates were made for the job - any idea what they came off?
88

88 They came with the cigarette lighter sockets that I use as power output sockets on the bikes..... from Maplins.

Paul.

My previous post seems to have vanished into the ether so here it is again:

What a great idea, as a computer tech I have loads of these fans kicking around and am also troubled by the condensation issues on my K100RT - I will look into this solution at the earliest opportunity

As this is a 'how to do it section', I've just taken the speedo off the solo to photograph the inside, showing a bit more detail. Note that the fan needs to be inset through the back plate; otherwise there won't be enough clearance for the intake side of the fan.



As you can see, after blakey's concern, there's no evidence of dust or dirt getting in after 3 years use. Also I,ve thought of a criteria for deciding if a filter is required; if you can write your name in the dust inside the alloy base cover, then you may need a filter. Mine, fortunately was clear!

Paul.

A neat piece of Brummie engineering!!

nice one paul ...congrats

What a great idea paul first class piece of work

BIG D

I will be looking into this idea in more detail before the summer months set in (ok, obvious joke there). It seems like a great idea and relatively easy to implement.

Before resorting to adding forced ventilation can I suggest that trying sealing the cluster using the sealing process discussed at length in the discussion on LED's in the instrument cluster below. After doing all the mods except the odo wind back knob I still got misting. Once I sealed that with the special synthetic Tef Gel grease no more misting at all.
http://k100rt.aforumfree.com/t223-led-lights-in-the-instrument-pod-plus-sealing-out-the-moisture?highlight=instrument+cluster
Regards,
K-BIKE

Hi K-BIKE,
Yes, it's worth trying, but BMW modified the sealing at some stage, so early clocks may be more difficult to seal completely.
Another point is that when using the standard illumination bulbs, there is a minimum of 15 watts of heat build up in a confined space, so some cooling air is probably not a bad idea.
Paul.

sidecar paul wrote:Yes, it's worth trying, but BMW modified the sealing at some stage, so early clocks may be more difficult to seal completely.

83-85 did have 7 screws on the rear of the cluster, from -86 on 10 screws was used.

Inge K.