My 06 is giving me a hard time. Yesterday i went change the engine oil, replace air filter and spark plugs. Previously i had noticed that sometimes she would idle only at 2k to 2,5k rpms... couldn't find the exact cause of this... Today took it for a wash and do the "15 minute idle not touching anything" procedure to let her reset her thoughts.. No matter what, the idle still kept at 2,5k revs which may be an el cheapo cruise control, but not very good. Time to check the TPS....? At the garage i noticed the coolant reservoir was dark and a bit too full. when removed the coolant cap, put one finger in and... sludge! F....k..., removed the radiator cap and a bit sludgy too, the coolant had a brownish color. I'd say theres a leak somewhere, but consider this: Drained exactly 3 liters of oil. Oil color was black! No traces of milky stuff Oil filter was clean without any weaves (does this sound right!?) Bike is 50k kms, water pump shaft and seal was replaced 20k kms ago. Dunno when was last coolant flush done Spark plugs were good. Brownish tan, no soot, no wet residues. While doing the 15 minute procedure in the outside, temperature was mild 25º, little wind, it never went above 4 bars, and i could only hear the fan going on after 14 minuts of idling still. Some pics: Oil filter: Coolant reservoir: Coolant in the overflow reservoir: Looking closely it seems the liquid is not mixed and slowly separating by gravity: I'm pretty headed to oil mixing with coolant scenario but i find strange not the other way around. Coolant does not show viscosity, could it be the coolant loosing it's properties and degrading? What do your experience tell?