I did a fast woods ride this past weekend with some big bikes and quads. I noticed the bike was running very hot. Checked the obvious, (fan was working, coolant was full), and everything seemed fine. Decided to check the impellor to make sure no fins were broke. When I took out the drain plug, first almost clear water came out, followed by a blue water and then by a sludgy blue mess. Kind of looked like paint, but a little thicker. When I took the cover off, more of the sludge was around the impellor.

ANY IDEA on what this is?

In case it matters, I ride a 04 Rev 3 250

Thanks

Coolant after a period of time loses it`s anti corrosive properties allowing the water in your mixture too start the dreaded oxidising process, a few Beta`s have been known too have casings with a certain alloy type that corrode quite easily, your best bet is too check your casings. Hopefully you will have caught the problem in time?

It is very important on an engine of this size with such small cooling jackets too keep on top of your fgluids and change them regularly, I`ve not had mine long but will change my coolant at least 6 monthly, any slight blockage in the system could cause massive headaches and big un-needed bills in the long run.

This said one of the r2w riders had a slight rot problem round the impellar shaft area (I think it was) he bought a new case I think was about

Yes this happens if it has got really hot and seems to separate out the solids in

the coolant my 06 was just the same .if they have boiled up badly it will corrode

the inside of the pump housing,this happened to my mates bike.

You need to change the coolant at lest once a year and if it's been boiling up

replace it.

it happened to me after using the recomended repsol stuff cost

Thanks for the help, looks like I caught it in time as there is nothing even close to resembling that photo.

So if I'm hearing correctly, the cheap cases caused the breakdown on the coolant and thus the overheating problem?

Based on the earlier posts, the overheating caused the coolant to breakdown and thus would leave me to still try and determine the overheating problem.