[TomJohnston]

Never saw this before. 2014 C5 10k miles. Serviced religiously. Driving fewer miles at a time and not getting the engine as hot as I probably should. Currently riding in 30 to 40 degree weather.
This oil change was not black like it has always been till now. It's chocolate brown, like coffee with a couple shots of milk.
The spark plug is fowled with soot and the exhaust(standard catalitic muffler) is also carbon coated.
Runs good at full throttle but misses a little while cruising.
Summed up:
Black spark plug
Black tail pipe
 "Brown" oil
Sporadic miss, but okay at full or half throttle.
Any idea as to what's going on??

[Guaire]

Usually, a sooty plug means you are running rich. Is your air filter plugged up?

[Richard230]

Brown oil means there is water in the oil, likely caused by condensation due to not getting the engine hot enough to vaporize the water out of the engine. This can happen even to air-cooled engines if they are not ridden long enough and stored in a cooled and damp environment.

[gizzo]

Brown oil means there is water in the oil, likely caused by condensation due to not getting the engine hot enough to vaporize the water out of the engine. This can happen even to air-cooled engines if they are not ridden long enough and stored in a cooled and damp environment.

Yep. Sounds like it needs an oil change and a wog tune.

[Bilgemaster]

Yep. Sounds like it needs an oil change and a wog tune.

Tom: As you appear from your profile to hail from Pennsylvania, perhaps one should clarify that "wog tune" is the Australian equivalent of our North American "Italian Tuneup" (or, rather more potentially derogatorily, "Wop Tuneup"), as helpfully described on Wikipedia here: https://en.m.wikipedia.org/wiki/Italian_tuneup.

Please be advised that whereas "wog" in Oz may be a fairly neutral slang term describing those of a "Mediterranean" cast, such as Greeks or Italians, in Britain those could be "fightin' words". So, best not to stumble out of a pub in, say, Nottingham bellowing, "I could really go for some wog food!", or you might well discover a "knuckle sandwich" on the menu instead.

But yeah, change the oil and filter, clean up, or perhaps replace the spark plug, take that thing for a nice long "spirited" ride, and, as they say in the Haynes manuals, "observe effect on performance".

[Morgan65]

Brown oil means there is water in the oil, likely caused by condensation due to not getting the engine hot enough to vaporize the water out of the engine. This can happen even to air-cooled engines if they are not ridden long enough and stored in a cooled and damp environment.

Plus one,
Definitely water issue with brown oil and some milk, some call it yogurt in the oil. I let my motor warm up for at lest five to six minutes before riding, then I do at lest ten miles of riding before I shut it off.

[TomJohnston]

Thanks to all. I was afraid I might have a electrical or computer problem.
A long ride is on the schedule.

[Mad4Bullets]

If there's moisture in the oil, there's a very good chance you have water in your gas as well, thanks to Ethanol.  I suggest you replace that before your long ride and add some fuel injector cleaner as directed. I use Techron from Mobil and I'm pleased with the results.  Good luck.

[axman88]

Riding this time of year, at least in my area, can mean cold humid days.  If you can see your breath, the likelihood of crankcase condensation and vapor in your exhaust, increases.  In both places, the water will be driven off by extended running at higher temperature, and can cause problems if allowed to persist.

This has to do with the dew point relative to the ambient temperature, and is not simply due to low temperatures.  Low temperatures with low humidity are much less problematic, although water is always produced when burning petrol.  Google, "Fog", if you want more technical discussion.

[Karl Fenn]

Well that can be caused by short journeys and moister in the oil, l used to get that on my BMW GS 650, a lot of people get the same issues on cars, give your bike a good service including the carb and plug that should cure these issues smell the oil for any petrol as well.