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K100 Radiator Fan - home made controls?

ChrisM47

New member
My FYK100 has been reliable for the 4 years I've had her, but recently the radiator fan has stayed on when parked after a ride, not turning off till disconnected.
The PO had installed a rheostat, temp probe and manual on/off switch, that now is important in the troubleshooting process.
I have Tom Coradeschi's excellent cooling system troubleshooting guide, and would remove this mod first unless someone has knowledge of it.
Has anyone seen such a mod to a brick K bike?
Thanks in advance for any help.
Chris Muscarella
 
First thing to do is make SURE that the coolant level is full AT THE RADIATOR CAP not at the overflow bottle.

If level is ok, you are probably looking at a bad sensor, rheostat, or switch.



:dance:dance:dance
 
Thanks for the suggestion Lee.

Since I became the owner I've wondered if the added rheostat that is tie wrapped to the frame behind the air intake and the associated temp probe inserted into the radiator fins were added to replace a faulty temp sensor??? But all seemed to work fine winter or summer so if it ain't broke.....

I did check the coolant level at the cap, and do suspect the temp sensor. I did change the coolant last June and all was well till last December, no leaks or need to add coolant, only the run on fan.

I also have an R1100RT but actually get more grins on the Brick!
 
Some owners did put in a manual fan switch

Since that bike runs HOT, especially in your neck of the woods. Probably not a real problem if it runs all the time when riding, since most of these fans died from lask of use rather than over use! Having it run after you've turned the bike off is another matter....:blush
 
Some owners did put in a manual fan switch

Since that bike runs HOT, especially in your neck of the woods. Probably not a real problem if it runs all the time when riding, since most of these fans died from lask of use rather than over use! Having it run after you've turned the bike off is another matter....:blush

It makes sense to have a manual fan switch to assure the fan can be turned on in case the relay or temp sending unit fail, assuming the rider is aware of the need before the engine overheats.

The rheostat and the probe in the radiator fins must be there to replace a faulty part or to change the temp control parameters. i was hoping someone on the forum had some experience with a mod of this type and could advise how to troubleshoot the problem. I'll give it my best shot this week and post my findings here.
 
Cjm -

Right. The manual switch was usually put in in an effort to reduce the engine temps - so it could be turned on before it entered the 'red' zone. I neved did this up North here, so perhap the PO installed it BECAUSE the factory system for activating the fan had failed.

Good luck in your efforts to resolve.
 
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