Coolant leak from cylinder port
 

I have a coolant leak coming from the port on the lower front left side of the cylinder. Seems to only do it when i first start it up. It kind of spits out, not a steady dribble. Once it warms up it doesnt seem to leak. After 2 hrs of riding i can see the top of the rad fins so it must be leaking a bit once its warm. This port has a drain tube on it but i dont know what its for. 05 ec250. Any ideas? Thanks, sam.

That port is for the powervalve to drain excess spooge. Shouldn't have water/coolant entering there. I'd be removing the side cover to investigate further.

Ok thanks, I will investigate. I thought it was just condensation at first but my coolant level is dropping so I assumed it had to be coolant since its a decent amount. I guess I should say that I cant really confirm its coolant cause its Black/Grey water like substance. Can you run the bike with the pv left side cover off??? Might be able to see where its coming from.

Your water pump seal may be leaking.

I think you can, but I believe it will be very noisy.

For inspection purposes nothing wrong with running the engine with the side cover off (either side).

Given what you have said so far it may be that nothing is wrong.

If what is spitting out is black and oily it will be spooge (unburnt fuel/oil) and it's likely that while the engine cools and sits it will pool at the port in the side cover. When you start the engine the pressure will blow out what has pooled. Once running it shouldn't be as much. I would say spooge is much thicker in consistency than water though. If water is mixing with the spooge you'd to see it.

In relation to the coolant level. Does the bike have an expansion chamber/coolant reservoir? Not sure if the 05 models did. My 2010 had one around the front of the head stem.

If it doesn't it's normal for the rads to push out excess coolant as it expands. Usually this results in the coolant level dropping to be just across the top of the fins once cooled down again. If you top it up, it pushes out next time you run it up to temp, and so on and so on. I find tilting the bike slightly to the left/right allows you determine the actual level across the fins. If it's right on I'd go for a little ride and monitor it closely. You may find it doesn't drop any further.

I sure hope its nothing! I changed the gearbox oil and coolant today. No water in oil or oil in warer. Pulled the side cover and started the engine. After about 5 sec a decent amount of moisture comes out of the machined port area just above the powervalve bearings. Its an aluminum/grey color, has the consistancy of water, and isnt black like spooge. It quit after a few mins. Put the cover back on and rode around the yard. Parked it and let run and not another drop. Let it sit for about 20 mins and strated it again...no drops. I cant beleive that much moisture comes out of the engine but that must be what it is. Been cold at night here, prob around 40 in the garage. Thanks for the tips. Going to try to get a good hour ride in tomorrow so i will update if i have any issues. No reservoir on this bike.

There is humidity in the air and water vapor is a byproduct of this combustion process. Liquid water can be formed depending on the combination of exhaust temperature and ambient conditions. If the parameters meet the dew point conditions, then liquid water is formed. It is possible the water is condensing and dripping off the cold cylinder in the power valve area.


Dew point From Wikipedia,
The dew point is the temperature to which air must be cooled to become saturated with water vapor. When further cooled, the airborne water vapor will condense to form liquid water (dew). When air cools to its dew point through contact with a surface that is colder than the air, water will condense on the surface.

Head Orings leaking?

I'd be cracking the crankcase drain bolt and seeing if anything comes out.