easiest way to replace cooling fan on 1985 krt 100?

[pinhead]

I have a 1985 KRT 100 that I noticed was overheating when I got stuck in traffic in the middle of a 100 mile trip.  The red warning light came on but went out thankfully as traffic started to move again. 

I tested the fan and it is dead, i.e. applied 12 volts and it did not turn.  Also, when you turn the blades it does not turn easily as a fan I presume should do.  So I get it, I have to replace the fan.

I have previously taken both leg fairings off this bike since I couldn't bear the smell of my legs being roasted to medium rare in the heat that I live in.  That being said, it appears to me that still the easiest way to get at that fan is to remove the radiator.  Am I right or is there an easier way? 

Still riding the bike but not in the heat or traffic.  The cooling fan, when it was working, rarely came on anyway.  Was thinking of carrying a spray bottle to use if I unexpectedly got stuck in traffic and could pull over, let bike idle and spray water on radiator to keep from busting a hose or worse on the engine.  Since it rarely comes on anyway, and only when I am going slow or not at all, I would think the evaporative cooling of the water on the radiator would be as good as a fan.  Any thoughts? 

[mw074]

Do it right. Replace the fan.

[Martin]

The OEM fans were susceptible to dirt and water ingress, and in order to keep them going had to be run frequently. I replaced mine with a Davies Craig fully sealed car one about 18 years. I also fitted an override switch so I can run it at anytime. There are posts on conversions, with my conversion I kept the blades and the outer plastic housing minus the motor support arms (cut off ) . I then cut off the outer part of the Davies Craig housing which consisted of concentric rings. I put the Davies  Craig housing over the OEM housing lined up the concentric circles with the OEM housing and cut off the outer rings. I then made up some clips which went over the last remaining ring and riveted it to the OEM housing. I think I had to drill the OEM fan hub to fit the Davies Craig motor. I cut off the wiring of the OEM fan and attached it to the new motor, make sure it rotates in the correct direction. It has never missed a beat.
Regards Martin

[Laitch]

Since it rarely comes on anyway, and only when I am going slow or not at all, I would think the evaporative cooling of the water on the radiator would be as good as a fan.  Any thoughts?

mw074 is right. Martin is right. I'm right.

Remove your radiator and replace your fan. A Spal fan makes a suitable replacement. Fill your spray bottle with moisturizer or aromatherapy balm and use it on yourself.

[Martin]

Laitch I thought I was wrong once but I was mistaken,
Regards a humble Martin.

[Laitch]

You're a bonafide template of humility, Martin!

If your coolant is less than two years old, pinhead, drain it into a clean container and reuse it. Otherwise take this opportunity to replace it.

[pinhead]

I take it then, the easiest way to replace the cooling fan is to remove the radiator.

[Martin]

 :2thumbup: You got it, it's not hard just a bit fiddly and a good opportunity to replace the coolant ( as per Laitch ) and check hoses and flush the system. The reason I converted mine is I had only just bought it and on trying to get a second hand one was told it would cost me $200.00 for a complete one, motor not available separate. I read up on the fan which was a known problem and weakness, and bought a Davies Craig on special for under $50.00 Au. If you go with an OEM fan motor which I believe you can now get, fit an override switch which is essential if you want to get any mileage out of it.
Regards Martin.

[The Mighty Gryphon]

http://www.motobrick.com/index.php/topic,4313.0.html

Go down to post #18 by Roadbandit on December 20, 2014.

I followed his description when I put a Spal fan on my K100.  The actual work to get the Spal into the old frame took less than an hour.  Has worked fine for over a year and 5000+ miles.

[gone_ape]

Chris Harris put out a very short vid here:

[Vespa no more]

Regarding the fan... a question

While doing other things, pulled the radiator, flushed and cleaned it. All fine here.

Pulled the fan off and tried to service it. After compressed air, applied some light oil to the rear bush / bearing but could not get at the front (fan) end. Unhooked the brush spring and cleaned the commutator with very fine wet and dry. Put it back together. Did not want to fix what was not broken and did not attempt to dismantle the fan any further.

Q: How to access the front bush / bearing?

Will ultimately replace fan with recommendations in earlier comments but not just yet.

Regards
Guy

[The Mighty Gryphon]

The fans are crap, I wouldn't waste my time trying to make it work(Already been down that road, so I know what a waste of time it is).

Bite the bullet for the Spal fan and spend the hour to retrofit it.  Do it now while the bike is apart.  You will be glad you did.

[Vespa no more]

But I JUST put it back together...

Oh well, seeing I've got my eye in ... better pull it apart AGAIN
Thankfully, local auto shop can get any model in over night... $110 AUD

So I guess there are several options but height must be the main concern.
Dare I ask which model is recommended (if there is more than one 6.5" pull fan and the model shown on this post earlier may now be superseded)

And regarding the switch, apart from going to the local Jaycar / Tandy electrical shop, are there any other concerns regarding installation. I don't want it looking like the bodge on my K100RS.

Thanks for your thoughts

Regards

Guy

[Laitch]

So I guess there are several options but height must be the main concern.
Dare I ask which model is recommended (if there is more than one 6.5" pull fan and the model shown on this post earlier may now be superseded)

Here is the post that has a link to the current model number of the fan replacement discussed in this thread and others.

[Vespa no more]

Thanks for that Laitch

Was wondering if a new improved model had hit the market. Apparently not.

Will probably go with splitting the existing housing as easiest and closest (visually) to original.

Once done will post feedback if a lightbulb moment occurs

Regards

Guy

[Martin]

Euro Motoelectrics have new fan motors for $79.00  Plus Freight.  http://www.euromotoelectrics.com/Cooling-System-s/5.htm
Regards Martin.

[Vespa no more]

Have decided to keep working BMW fan intact

Have made template to mount Spal 6.5" fan.

If the radiator is 8" high - why go for a 6.5" when I 9" could be fitted with the fan twisted so that the mounting points fit?

This means of course putting bolts through the radiator cooling fins (have done it on a car using a No2 Phillips head screw driver - looks a bit amateurish but works fine) - but there is no damage to the integrity of the radiator and its operation.

Of course I would much prefer to mount the Spal fan inside the BMW fan housing to have look as original as possible - but I aint got a broke one.

Am currently looking through the Spal catalogue...

Thoughts welcome

Regards

Guy

[Laitch]

Have made template to mount Spal 6.5" fan.

If you've made the template, why not just go ahead and do that which others have done successfully? Not enough drama down there?

[Vespa no more]

Too much is not enough

Underwhelmed by the bodgy (US equivalent: "Half Assed") switch modifications I've seen around, I commandeered one from the K1100LT - pleased that this would look "original". Of course one of the wires had come away from the solder and the other soon followed.

The template I have cut probably needs to be a heavier gauge - for those following this path try 2 or 3mm thick. Am thinking the street sign I used is a little too flexible. The BMW fan has reinforcing that strengthens the whole unit - no doubt because of the depth of the fan (approx twice that of a low profile Spal)

Spal catalogue: (I'm sure there are cheaper sources)

https://www.a1electric.com/catalog/cat_spal.htm

Next bigger (than 6.5") puller fan =7.5":

http://www.a1electric.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=AEOS&Product_Code=30100358

6.5" = 330cfm
7.5" (a cyclonic) 440cfm - guaranteed to my YOUR bike go faster! Forget the RS gearing, K1100 implant, streamlining of tragkorbs, strap-ons, shaving of beards (and legs)...

So: if your fan is kaput and you want the original look (by cutting the shroud in half and hiding the new fan inside - the 6.5" is the ticket.
If bigger is better, the 8" high radiator would surely take the 7.5" (and it's cheaper apparently)

Now to return the smaller one and figure out the wiring.

I guess my students' essays might have to wait another day. They'll understand. They better - or they fail.

Regards

Guy