K75 cooling system

[SCOOTERTR6]

just picked up a 1990 K75. Runs good but noticed it was running hot. Warning lights did not come on.Pulled the radiator and hooked up the fan to a 12v Battery. It turned but very slow and pulled what I would describe as a gentle breeze. ordered a new one from SPAL.

I bench tested the thermostat and it opens at the correct temp. I SUSPECT the temp senor is shot. But I don't want to start digging to deeply into this machine the first week and these K bikes are known for slacking on activating the fan circuit.  What I would like to do is install a switch on one of the slots in the dash and just let the fan run while riding around Houston which is 90 degrees most of the time. I can switch it off on the open road .

Not sure if that sensor communicates with the computer that keeps the engine and fuel injection in balance though and the Clymer manual doesn't include any diagnoctics on testing the sensor or description of it's functions. Hoping to run into a K bike guru. No k-75s or 100s around here. I don't think there more than a hand full of them in TX. I've never seen one in the thirty years I been here  I've got some experience with them.though.
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I BOUGHT a totaled k75 in 1988 that was in a high speed crash  and got it running pretty easily. It didn't run into anything just slid on the pavement  for a while and ground all the fiberglass off .  needed handlebars , brake and clutch levers rear brake pedal and 1 radiator hose. I put a black leather tank cover on it to hide the damage  Painted tha scuffled fenders with flat black paint and some exposed tube structure then rode it naked with the mandatory laughing skull sticker on the leading fender. It actally looked pretty good and was the only punkrock road warrior rat bike KBMr in the SF Bay Area .Even the BMW stock purists couldnt resist snapping a picture. I also had a TRIUMPH Bonneville TT and a NORTON Commando Interstate, but scoring a two year old K75 with only 1600 miles on it for 500 bucks was the best deal I ever got.

Also lucked out on this 1990 k75 s which really is the best design IMO. THIS one I can pamper,

Edited July 1, 2021 by SCOOTERTR6
grammer

[Veefore]

Maybe there would be some answers here -

https://ibmwr.org/index.php/2007/06/01/cooling-fan-diagnostics/