Question On Black Brake Fluid

That's not right! The fluid should hardly have discoloured after 2 years. Tests can be carried out to see what the contaminant is but it should be changed as soon as possible.

It's unlikely that it is from the brake lines as they should be braided brake lines on the Speed Twin. When you have it serviced ask the dealer to have a look at it. Is your bike still covered by warranty? That problem should be resolved before riding the bike much further

 

Are you sure it's the brake fluid you are looking at? Have you removed the reservoir cap and looked inside? It has been known for the black rubber diaphragm to become distorted and visible.

 

That makes no sense - brake fluid would not turn black unless someone has opened the reservoir cap and put something in it. You haven't got an annoyed vengeful squid as a pet have you?

 

I recently had my 21 Tiger serviced at only 7500k brake fluid changed as it had moisture in it as apparently it is a hydrostatic liquid which as I understand it attracts moisture and because of modern abs systems it is important to have it changed regularly as the moisture can damage the abs mechanicals but I did notice that the fluid when changed was almost different as day and night in colour comparison but certainly not black but quite dark brown

 

[QUOTE="Trierer, post: 663920, member: Still, this shouldn't effect a closed system as the brake system is (or is supposed to be). [/QUOTE]

Brake systems aren't fully sealed 100% and if you think about it can't be.

Pad and disc wear need to be allowed for. Consequently the pistons move out and the fluid level goes down in the reservoir.
What is above the liquid level?



Answer; ambient air via the breather route.
High humidity means the hygroscopic fluid will lower its boiling point due to water inclusion.

 

@Trierer if you look at other bikes or cars do they have similarly affected brake fluid showing in their reservoirs?

 

I have been fettling bikes for a very long time and i have never seen anything like that. It's hard to see from the photo whether the plastic reservoir has discoloured or if it's the contents. Have you removed the cap? perhaps dip a piece of clean paper in and see how it comes out.

When I was a lad a farmer emptied his sheep dip tank into a field and it the result was that it affected a lake some miles away by giving the green light to some organisms; I think the sheep dip perhaps killed the organisms natural predator, but the net result was that water in the lake was very densely coloured for quite a while. I don't remember the details given it was the best part of five decades ago, but after a year and a half the chances are that there will be quite a lot of moisture in your fluid given it's such a humid climate. In the UK bugs get in diesel systems and wreak havoc sometimes, particularly in boat engines especially yachts where the diesel is seldom used and is stored for long periods.

In your situation I would be loth to trust a bike dealer to flush out the system properly. Personally I would strip the entire system including removing the pistons from the calipers and wash everything out with plenty of brake cleaner. If it is a bug in the fluid it will doubtless multiply again as soon as there is some more water for it, which probably won't take that long in such a climate. In the UK I change brake fluid every other year, but test the water content annually. Brake fluid is pretty cheap, but the result of brake deterioration isn't and can be fatal.