Pixie dust in my coolant???
 

Owing to a rainy, windy day, the first day of 2016 has been a garage day, and I have been replacing some coolant hoses deep in the v. Aside from an interesting discovery of a Japanese coin lodged at the bottom of the V, I did find that the coolant has what appears to be very fine shards of aluminium floating in it. So fine that they generally stay dispersed in the liquid.

Is this a forewarning of something unpleasant like a water pump failure? The bike has 72000km on it. I have opened up the water pump, and the impeller and casing look completely unmarked. Just flush the cooling system,replace the coolant and forget about it?

Fine aluminum particles most often mean one of two things... water pump failure is in progress (impeller is touching the housing or cover or both) or at some point the water pump was "rebuilt" and not done so correctly. The impeller and shaft were not set to the correct depth and the impeller rubbed the housing or cover.

If you have checked the waterpump, seen no sign of the impeller touching, no excess movement of the impeller shaft related to the bearing.. and no leaking of coolant out the weep hole... then I'd flush the coolant, start fresh and check it again in a few thousand K's.

Thanks for the comments. The impeller was clear of the engine case by about 3mm, and absolutely no sign of contact with the outer case.

http://i629.photobucket.com/albums/u...4/IMG_2158.jpg

http://i629.photobucket.com/albums/u...4/IMG_2159.jpg

So I flushed the coolant lines out and put in fresh coolant, and will follow your suggestion and check this again in a few thousand k's.

How did you go after your test ride??

Running like a champ with no unusual external symptoms. Before the ride I let the bike heat fully until the fan came on and then off a couple of times to check for any leaks or errant behaviour. During the ride the cooling system did it's thing perfectly and no leaks.

did you check in the rad again for "pixie dust"

Not just yet; that's a fairing off/coolant drain exercise, and I will run for a couple of thousand km before I do that I think. The obvious source (the water pump) looked fine internally, so I've decided to wait this one out.

Cool

I drained the coolant out today so i could get under the clutch cover for a bit of a look at the clutch and drive gears.

No pixie dust this time, and thinking back I wonder if the last time I drained the coolant was the first time the front head drain had been opened. I suspect a bit of debris would build up in that low spot.