2012 KX250F overheating.

Yes there is a coolant drip hole under the water pump. It is there to let you know if the seals are leaking. You will loose coolant if the seals are bad. You will new seals and bearing for the water pump. Also the radiator cap is most likely weak and should be replaced with a higher pressure unit.

Paw Paw

I have the same problem with my 2011. I ride trails often and it does fine moving but if we stop for a bit I leave it idling and it gets hot instantly almost. I see pro circuit bikes have a overflow catch tank that recirculates the water back into the radiator. Or I think that's what happens anyways. I might try and see if I can do something like that.

I faced the same issue with my 2012 KX250F a couple months ago. Thought it had something to do with the water pump so I went all out and changed the stock one to a Boyesen. Still had the issue...turns out the radiator cap wasn't holding pressure so the pump wasn't able to move water like it was supposed to. I would take a look at your radiator cap just to see if that's it, in which case would be a cheap fix.

You should be able to tell if your pump is working or not by taking the radiator cap off, starting the bike and seeing if the coolant is flowing as it should be. Long story short, I replaced that shaft a couple of months ago when I over torqued the bolt that bolts the impeller on and snapped off the head. As a heads up, that shaft needs to have the gear pressed off and then it will need to be pressed on to the new one so you're going to need a press. Also, be careful when tightening the impeller bolt, it doesn't need much at all!

Here is a picture of mine. My bike is a 2014 kx250f.

All modern race 4 strokes will puke coolant if it sits and idles any time at all. Engine Ice helps a lot as does a higher pressure radiator cap. We offer them in 1.8 and 2.0 for your KXF