overheating problem

[arkman84]

i have a 1985 k100. I have owned it now for 2 months. A couple days ago i noticed the overheat light came on. Coolant level is good and flowing. i burped the system just in case. there is no leaks anywhere. What i did notice though is that the fan doesnt come on. my question is, would the bike overheat within 5 minutes in idle if the fan doesnt work? ( also it was about 87 degrees outside that day) thanks for any help.

[Motorhobo]

Yes, it would, depending on how fast you're moving and how much cool air is passing over the engine. If you're not moving on a hot day, it'll heat up pretty quick.

If the light comes on, pull over and wait till you have a clear road so the air can cool the engine. Don't ride with the light on - you can damage old and brittle rubber bits on the throttle bodies not to mention other hazards of overheating a gas engine.

[arkman84]

where is the best option to get a new fan? does it come as a whole assembly or separate pieces?

[Inge K.]

Usually the fan fails is caused of melted brush holders, which is a result of a seized fan.

http://www.euromotoelectrics.com/category-s/866.htm

http://technik.flyingbrick.de/images/b/b9/17_Lueftermotorreparatur.pdf

[johnny]

greetings arkman84...

some buy used... some buy new... some fab up something different...

i buy used and replace the entire assembly motor blade housing...

bike breakers here... http://www.motobrick.com/index.php?board=46.0

j o

[Grim]

One of the members here had made some adapters to make common parts store fan a bolt in. There is a couple threads about this. Either search within th forum with "fan" as the search words or Google "motobrick.com fan"

[pkrhd]

I replaced the fanmotor on both my K Bikes with a motor from euro motoelectrics. Its an exact fit Bosch, only thing you have to do is solder the wires on as the plug in connectors won't let you put the cover back on.

[mjydrafter]

One of the members here had made some adapters to make common parts store fan a bolt in. There is a couple threads about this. Either search within th forum with "fan" as the search words or Google "motobrick.com fan"

 

Here is my thread on a better replacement than stock:http://www.motobrick.com/index.php?topic=4313.msg29942#msg29942

I think there is a template for the adapter plate linked in the the thread, or IIRC I have one plate left.  Not trying to be a schill, just sayin'. :yes

I think even with the fan and adapter, you are spending similar $ for a stock replacement.  The other thing to consider is the blade mounting on the stock one, it can get loose and drill into the back of the radiator.  There's a bad pic of that in the thread referenced.