Hi folks!
I got my 1985 K100RT back together after replacing the rear main seal and I am on the road. Yesterday, after sitting in traffic for over an hour my temperature light came on and shortly after my bike died and I quickly pulled to the side of the freeway. After inspection the coolant had blown out of the reservoir. I was able to get more coolant back into the bike, but could not get it started. After fiddling with things for a few hours I finally called a tow truck to the nearest BMW dealership. I called them this morning and they can't look at it today. It seems like maybe the bike is not getting fuel. I pulled the plugs and they seemed dry, no coolant leaks, I think the fuses are ok too. Well, I am stuck with no one to help. Both BMW shops near by are overbooked today and can't see me till Tuesday.

Any parts that I could try swapping out?

Any advice is much appreciated!

Brandon

Hi Brandon, bike stops automatically after coolant reach 113 degrees, but could restart after ten minutes. Do you hear the pump when push ign. button. If you can fuel will normally flows (except when filter clogged), if not check pump fuse, than pump relay (usually orange one at the left front corner of relay box. Could be a pump but first check easier solutions. Try to swap relay with new one just for test.

Regards

Nino,
Thanks for the tip. Yes, the pump is working. I finally tracked down someone who thinks it might be the haul sensor/trigger, which would take some significant work to get fixed. I have a buddy who is driving way out of his way to come pick my broke ass up. Looks like another garage project.

Regards,
Brandon

docious wrote:Nino,
Thanks for the tip. Yes, the pump is working. I finally tracked down someone who thinks it might be the haul sensor/trigger, which would take some significant work to get fixed. I have a buddy who is driving way out of his way to come pick my broke ass up. Looks like another garage project.

Regards,
Brandon

Good luck. In half an hour you can replace hall sensor. As I understood my friend mechanic its same hall like on some types of VW golf.

Regards

First, your fan should have kicked in and cool down the bike.
Check if the fan is working (apply 12v and see if it's rotating). The water temperature sensor is a double one. One side is controlling the fuel injection and the other side is controlling the water temperature unit (overheating warning light and starting the fan)
The electronic will never shut down the bike if it overheats, but will prevents restarting by shutting down the fuel injection.
Failing Hall sensors will act up when hot. They should be OK when the bike cools down.
Check the troubleshooting page to find how to test them.
Replacing the Hall sensors is a 1/2 hour job if the tank is off the bike.

CF

Your overheat light came on so you do have a problem somewhere with the fan.
First see if you can rotate the fan by using a small stick through the fairing at the right side.
Try unpluging the ECU computer and leave it for 1 hour then replug it and try. Sometimes these darling things get an idea in their very small brain that can only be removed by disconecting all power sources (life support) untill it comes to its senses.

I had a similar problem but at temperatures over 30s. my fan was working but not at full speed ... they are rated at 4100 rpm and my was working at lower speed probably due to a band-aid fix of the brushes.

The temp light would com on in traffic and would disappear once i get going.

Thanks CF! I went through and tested everything that you laid out and everything seemed to check out. Today I after pulling the injectors realized I had a lack of fuel pressure. I opened up the tank only to find that my fuel filter had become disconnected from the fuel line. As soon as I reconnected that it fired up like a champ. I have no idea how my bike overheated and simultaneously disconnected the fuel line from the filter, but it did. Good news is my bike is running again.

-Brandon

Crazy Frog wrote:First, your fan should have kicked in and cool down the bike.
Check if the fan is working (apply 12v and see if it's rotating). The water temperature sensor is a double one. One side is controlling the fuel injection and the other side is controlling the water temperature unit (overheating warning light and starting the fan)
The electronic will never shut down the bike if it overheats, but will prevents restarting by shutting down the fuel injection.
Failing Hall sensors will act up when hot. They should be OK when the bike cools down.
Check the troubleshooting page to find how to test them.
Replacing the Hall sensors is a 1/2 hour job if the tank is off the bike.

CF

Glad to hear that, Brandon. The easiest way to check fuel system is to hit start button with left hand on fuel hose near the fuel rail. Usually one could feel the stream of fuel if everything OK. It saves a lot of time.

Regards

There is a lesson here for all of us how easy it is to think all problems are related to the incident, well done Brandon for checking and finding that.
Regards,
K-BIKE