Overheating, fan not running

[Exponent]

Hi,
Anyone know of a cause to this? Rode the bike today and it was overheating, got back and checked that the fan was running and it wasn't. Replaced one fuse that was blown and still nothing, fan is connected and everything. I checked the fan again with the battery and two wires and it works, so the fan itself isn't dead.

Somewhere between the fan and everything else its not getting power. Any ideas?

[Triple Jim]

What were the symptoms of overheating? My fan almost never comes on. It takes a hot summer day and a lot of idling in neutral to make it turn on.

[Exponent]

Originally Posted by Triple Jim

What were the symptoms of overheating? My fan almost never comes on. It takes a hot summer day and a lot of idling in neutral to make it turn on.

Temp gauge way up, smoking, burnt smell

[Triple Jim]

Originally Posted by Exponent

Temp gauge way up, smoking, burnt smell

Unless you were running the engine without moving, it didn't overhear because of the fan not running. Something else is wrong too. Yes, the fan should have come on, but as I said, mine almost never runs under normal riding conditions.

I assume you checked the coolant level. Maybe the thermostat is stuck closed.

[Exponent]

Originally Posted by Triple Jim

Unless you were running the engine without moving, it didn't overhear because of the fan not running. Something else is wrong too. Yes, the fan should have come on, but as I said, mine almost never runs under normal riding conditions.

I assume you checked the coolant level. Maybe the thermostat is stuck closed.

How would I check if the thermostat is stuck?

[Triple Jim]

Originally Posted by Exponent

How would I check if the thermostat is stuck?

Take it out, put it in boiling water, and see if it opens.

Here's the WIKI main page in case you haven't found it: https://faq.ninja250.org/wiki/Ninja250_Howto

[Exponent]

Originally Posted by Triple Jim

Take it out, put it in boiling water, and see if it opens.

Here's the WIKI main page in case you haven't found it: https://faq.ninja250.org/wiki/Ninja250_Howto

Any videos showing how to remove the thermostat?

[Exponent]

Update after running the bike again and riding around the block the coolant was low, that happened twice so coolant was refilled, hopefully its fixed.

[Triple Jim]

Originally Posted by Exponent

Update after running the bike again and riding around the block the coolant was low, that happened twice so coolant was refilled, hopefully its fixed.

Keep an eye out for signs of leaking coolant, including discolored oil, an extra clean spark plug, etc. Except for coolant changes, my 250's coolant has never changed level, so it seems that yours has found a way out.

[Exponent]

Originally Posted by Triple Jim

Keep an eye out for signs of leaking coolant, including discolored oil, an extra clean spark plug, etc. Except for coolant changes, my 250's coolant has never changed level, so it seems that yours has found a way out.

I drained some when I was fixing the exhaust collars

[How2]

Originally Posted by Exponent

Hi,
Anyone know of a cause to this? Rode the bike today and it was overheating, got back and checked that the fan was running and it wasn't. Replaced one fuse that was blown and still nothing, fan is connected and everything. I checked the fan again with the battery and two wires and it works, so the fan itself isn't dead.

Somewhere between the fan and everything else its not getting power. Any ideas?

Hello

There is one quirk that might be the culprit. The fan is actually coming on, but the bolt on the propeller is loose and its not spinning.

Or the prop is spinning, but not fast enough to cool the radiator.
You can hear the fan, but aren't noticing if the prop spinning like it should.

Check tightness on the fan bolt.

Maybe, just maybe.