Hi all I'm confused!! I have a switch mounted on the radiator just below the filler neck. The circuit diagram (https://2fiftycc.com/index.php?reso...ring-diagram-english.223/download&version=224) shows a thermo fan switch and a separate temperature sender for the over temp warning light on the instrument cluster. If I ground the sensor wire on the radiator temp switch, the temp warning light on the dash lights - so that doesn't fit with the circuit diagram. If I ground the sensor wire on the radiator temp switch, the fan doesn't turn on - which also doesn't fit with the circuit diagram (I've tested the fan with a 12V supply and it works). So this leads me to three questions: how is this actually meant to work? If there *are* two senders/switches, where is the second one located? And what temperature does the over temp warning light kick in? I can't find anything in the specs.
Thanks @GreyImport - you are 100% spot-on. The temp switch for the fan control is in the thermostat housing. Which seems a bit weird. I would have expected the fan control switch to be in the radiator and the over-temp warning light switch to be in the thermostat housing. I've now tested the thermo fan circuit (works) and warning light circuit (also works) So - while testing yesterday (engine idling for about 10 minutes, monitoring with an infrared thermometer, the temp in the radiator hit about 107 degrees Celsius without the warning light turning on or thermo fan cutting in. Is this expected behaviour? What temp should the water hit before the fan kicks in?
On the FZR the thermostat housing is a seperate stand alone unit and has both sensors on it As for your coolant temps I dont know exactly what degrees sets off the sensors I know in the days of my FZR being my road registered ride, I would return from a "spirited" ride and only after the bike sitting on the driveway idling while I took time to open the gate , would the fan kick in. This is some specs from the Kawasaki ZXR250A manual (as its in English) And just a bit of googling to get a rough idea on temps ..... https://www.riderforums.com/threads/coolant-temp-question.104904/ https://www.reddit.com/r/motorcycles/comments/ax3leq/bike_coolant_and_running_temperature/ If your thermostat is working or new and same with the radiator cap , then I would take it for a run and see what happens with the sensors and see if the temp changes with a bit of airflow .... and of course check the coolant level after the idling session from before
The impatience of youth... The fan kicked it today! I hadn't let it idle for long enough. The fan switch ON temperature is 95-100 degrees C. Switch OFF temperature is around 85 degrees C The boiling point of 1:1 water+ethylene glycol mix at 16 psi is about 129 degrees C so there's plenty of safety margin built in. No idea on the over-temp warning light switch but I assume it'll be well over 110 degrees C.
