Fan switch questions

[Track T 2411]

1489957158582156322076.jpg (119.95 KiB) Viewed 171 times

This is the point on my gauge that the fan switches on. It does cycle on and off every few minutes. The outside temp is 48 degrees. Should I be checking the gauge or the switch? I don't have an IR thermometer to check the actual temp of the coolant/engine.

[CYBORG]

I think your OK. Its keeping it in the normal temp range. Outside temp may be helping it stay in the lower end of the range. I would not be concerned. But it would not hurt to give it a double check when you can

[jdvorchak]

If you are really in doubt you can remove the radiator cap, engine cool please, and start it up. Use a cooking thermometer to read the temp of the coolant. Much more accurate than IR non-contact type. Auto parts stores also sell coolant thermometers pretty cheap but the cooking thermometer is probably a more accurate reading.

Here is like the one I use:

https://www.walmart.com/ip/Taylor-Profe ... /196307922

[Track T 2411]

I got a chance to check this out yesterday, using a digital thermometer directly in the antifreeze at the radiator. After the bike had warmed up and cooled down, I removed the radiator cap and inserted the digital thermometer. Fan turned on at 183 degrees f, ran for a few minutes, then cycled off and on continually, keeping the temp at about 178 degrees, but the fan would run for 30 seconds to a minute, off for 15 or 30 seconds, run for 30 seconds, etc. This was at idle, no extra fan, outside temp about 50 degrees. So it is warming up enough to keep the thermostat open, I think. Just don't want to fry the fan motor...

[jdvorchak]

When you get it running down the road the fan won't come on as often if ever. Put a big box fan in front of the radiator and do the test again to simulate running about 30 mph or so.

[Track T 2411]

...Put a big box fan in front of the radiator and do the test again to simulate running about 30 mph or so.

Yeah, I thought about that, but ran out of time. I'll give that a go, just to satisfy my curiosity...