contaminated oil

[divy dug]

Hi i have a 1995 yamaha xj900s diversion its an air cooled engine, and while checking to oil level i noticed there is white/cream sludge on the inside of the glass veiw port in the clutch cover and the inside of the oil filler cap
i think its water contamintion of the engine oil !
is there way of removeing the sludge without removing the clutch caseing

[Fisty]

Its condensation.
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Quietly and consistently taking the piss.
TL1000R | Hayabusa | ZXR400 | TL1000S | Bandit 400 V
Fatter and faster than Fret

[Hong Kong Phooey]

^that, air cooled so can only be that.

Do you do lots of short journeys?
Water evaporates eventually as the oil gets hot.

I'd take it up by the motorway for a bit then change oil and filter.
Not sure on your model but if the crank case breather is blocked then it could contribute to excessive condensation.
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'81 CG125, '97 FZS600 : '99 CBR600F4, '09 KTM RC8

[Travis Bickle]

Not sure how much this should be taken as fact but I've been told not to worry about this too much, impending doom is not necessarily imminent despite the ominous colour/consistency of the oil. Just change the oil and filter when you get time.
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Must Go Faster
1999 Yamaha FZS600 Fazer

[weasley]

In an air-cooled engine it can only be condensation, so not too much to worry about. In a water-cooled engine it might be condensation or it could be coolant, which is something to worry about.
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Yamaha XJ600 | Yamaha YZF600R Thundercat | KTM 990 SMT | BMW F900XR TE

[The Shaggy D.A.]

Someone is raping your oil filler and filling it with man juice.

Or condensation.
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Chances are quite high you are not in my Monkeysphere, and I don't care about you. Don't take it personally.
Currently : Royal Enfield 350 Meteor
Previously : CB100N > CB250RS > XJ900F > GT550 > GPZ750R/1000RX > AJS M16 > R100RT > Bullet 500 > CB500 > LS650P > Bullet Electra X & YBR125 > Bullet 350 "Superstar" & YBR125 Custom > Royal Enfield Classic 500 Despatch Limited Edition (28 of 200) & CB Two-Fifty Nighthawk > ER5

[stinkwheel]

Yes condensation. Go for a long ride. Mind you, sometimes it just refuses to shift from the sight glass in which case you might want to scrape it off the inside at the next oil change. You may even find you can clear it with a hairdrier.

An air cooled engine CAN produce lots of mayo if the bore is loose or valve guides are shot and you're getting a lot of piston blowby where exhaust gasses get into the crankcase (exhaust gasses are mostly carbon dioxide and water). You'd probably be having issues with it breathing oil into the airbox at the same time if this was the case.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[weasley]

A quick chemistry lesson. Oil and water don’t mix. It’s what we’re told at school and at a basic level it’s true. However you can make it ‘mix’ by adding something that will act as a ‘bridge’ between the dissimilar molecules of oil and water. A common such thing is a detergent. When washing greasy plates the detergent helps the water lift greases and oils off of the surface.

An engine oil contains a lot of additives, including detergents. They are primarily there to keep the engine clean of deposits and sludges but a side effect is that they also allow water to be absorbed into the oil. A little bit is ok and gets harmlessly dispersed. Too much leads to the formation of a thick and quite stable emulsion - it’s no accident it is often referred to as ‘mayo’, as mayonnaise is an oil/water emulsion too.

Sources of water include combustion by-product, atmospheric humidity and coolant. The emulsion tends to form in cooler, more stagnant areas such as dipstick tubes and filler caps. It can be corrected with heating - the water simply evaporates away - but a bad case may need physical intervention.
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Yamaha XJ600 | Yamaha YZF600R Thundercat | KTM 990 SMT | BMW F900XR TE

[The Shaggy D.A.]

Careful, Weasley - you're skipping on the tip of the Teffberg there
____________________
Chances are quite high you are not in my Monkeysphere, and I don't care about you. Don't take it personally.
Currently : Royal Enfield 350 Meteor
Previously : CB100N > CB250RS > XJ900F > GT550 > GPZ750R/1000RX > AJS M16 > R100RT > Bullet 500 > CB500 > LS650P > Bullet Electra X & YBR125 > Bullet 350 "Superstar" & YBR125 Custom > Royal Enfield Classic 500 Despatch Limited Edition (28 of 200) & CB Two-Fifty Nighthawk > ER5

[weasley]

I can out-Tef Tef on oil. One of the jobs I used to do included training people about oil. I ran a 6 hour course about engines and oils and that was essentially a summary.
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Yamaha XJ600 | Yamaha YZF600R Thundercat | KTM 990 SMT | BMW F900XR TE

[MCN]

[Fisty]