Black sludge in coolant overflow

Hi guys

Just wanted to clean the airfilter today. When the tank was lifted I noticed some black spots in the coolant overflow container, and took some pictures:




Here is what I found when I took the the lid off the overflow container:




This is what it looks like, up close:


It's almost like a fluid seal, or silicone you use for aquariums... it doesnt smell, is not that sticky, but I doubt it's a good sign.


What is wrong with the bike? I've googled and found it that it could either be the water pump or a blown head gasket?
I had the water pump changed to the new one last year, because I knew it had a fault. Maybe the shop changed it for the old waterpump thing, or didnt change all the things? Bike runs at the same temperature as it's always done! about 5 marks!
What do you guys think it is?

if you are not losing coolant your water pump seal should be ok.

I would remove the WP pipe and cover. stick a hose into the opening and flush it out. what you saw might just be residue gunk from who know what

I had the same thing in mine. It's shite left over from the casting process. Flush that crap out of the system as it won't do water pump seal any good at all.

Are you guys sure it's only leftovers from when the machine was made? When the water pump seal tihng was changed, they also changed the coolant, so shouldn't it allready have been flushed?
Maybe they just drained it, and filled up with new coolant, without flushing.. hmm

If they actually flushed the system I'd be amazed. Mine had the coolant changed at least twice and then the water pump seal went. Its a cast oil tank, not machined. Its the sand left from the casting process.

I posted my 'flushing' experience this on the ADVrider site
here's the link to the page with my pics - iPhone so the quality is iffy

Thanks guys, you are making me a little less angry at the bike

Will try and flush it in the weekend, hoping that it's just "sand" and that the 7000km old seal is not broken allready

flushed mine at about 8300 miles and so far no problem.....

Hi guys

A little update.
I flushed out the same way as SDsteph wrote, and when I tried to refill the engine, I could only put about 1,5 liters in, and the machine should take 2,1L.

Maybe all the fluid didnt drain completely, even though I flushed it in all holes, with good preassure and for a long time.. Hmm maybe it didnt just drain completely and thats why I can't fill all the 2,1Liters in?

Bu the way, my used coolant looked exactly like SDstephs, unclear and muddy.
Not as much "mucus" in the system.

I will just run the bike and watch out for missing coolant and then fill up?

filling the coolant should be done with the front wheel elevated, I tried but cheated and kept the radiator cap open and kept slowly topping off as the engine ran. I let it cool off and topped up again. I did this 2-3 times and it seemed to work for me.