Misty engine oil window

[bobhenry999]

Hi guys,

i am new to the forum having recently bought a 900.
I am about to change the oil and filter in my bike, but I have noticed that after a ride out, the window that allows me to see the oil level is all white and misty/foamy, almost like a water cooled engine when oil and water mix.

Is this a concern, or should I just change the oil and not worry, The bike runs perfectly by the way.

Thanks,

Bob

[zhango]

Welcome Bob and you are right - what you are seeing is water and oil mixed and it isn't good for the engine. The engine is not getting hot enough to evaporate the condensation so what you need to do is get the engine to above 85° C and you will not have a problem - short rides do not achieve this. One bad practice is to occasionally start the bike for a few minutes during the winter just to circulate the oil - if you are not going to ride it then leave it.

I have my oil cooler blanked off with cardboard, usually from Oct to May, and I can get the oil hot enough even in the winter. I went for a ride today and the oil reached 95°C which is ideal.

Many people will tell you this white mist in the oil glass is normal for a Monster and not to worry but that is wrong. It is common but it's not normal or desirable and eventually will cause engine wear so you can either just change the oil now and make sure you get the oil hot enough from now on. Alternatively, if you have got written evidence of a very recent service and it does have fresh oil you could go for a good ride and see if you can evaporate the condensation.

[Scott1]

That's really interesting Zhango, I've noticed this as well recently on my GT, which I think is the exact same engine as yours. The engine temp hasn't got above 85 since about September last year and its only really used for an 16 mile round trip to work and back through heavy traffic.

Once the warmer weather kicks in, it will get up to 85 every day no problem, big service due in November but I'll think about an oil change sooner.

[fireman sam]

One way to help the situation is remove the filler cap to allow the water vapour to escape when you park in the garage but Remember to replace the cap before you restart the engine

[scrapps]

Handy info zhango I start my bike and take it for a short spin round the block when I am not due to ride the bike for a while to keep things moving.
I will try to make sure I give it a long enough run to get the oil good and hot in the future and hopefully that will get rid of the misting on my bike.

[utopia]

And in case you're wondering where the moisture comes from in the first place, it condenses from moist air which is drawn in through the crankcase breather.
Obviously, this is going to be more of a problem in the winter months, even if you do get the engine fully warmed up, but short runs are not ideal for any engine, even in summer.
My Honda Dominator serves as a short distance runabout and winter hack, but being a big, single cyl engine the crankcase pumping, and hence the amoiunt of air exchange through the crankcase breather, is massive. There's no sight glass to see the condensation, but every few weeks in the winter I have to remove the cover from the starter gear chamber (the highest point on the crankcase) and remove the condensation sludge which has collected there. Sometimes I can get up to half a teaspoonful of pure water out of there if I've been doing very short runs. This doesn't do the bearings in there a lot of good, and indeed the squealing noise when the starter motor operated was what first brought this to my attention.
Its not just a problem on singles and twins though....I first noticed this on my 1975 Z1 Kawasaki which has much less crankcase pumping going on as the combined movement of its four pistons counterbalace their individual effect.
I sometimes wonder whether it would make sense to arrange for the crankcase breather to suck only warm, dry air somehow...maybe via an exhaust-heated chamber. Or alternatively to connect the breather to some sort of pressure accumulator (imagine a balloon connected over the breather vent) so as to isolate the ambient air. Both ideas are probably a little far fetched though, particularly the latter.

Anyone wanting to start the motor occaisionally in winter, to move the belts around and circulate some oil on a bike that is stored over winter, would be better to remove the plugs, inject a little engine oil into the bores, and turn the engine over by hand via the rear wheel.

[Nickj]

Plus any oil in the evaporates out and then condenses in the pipe up to the first part of the crank breather system, then it trickles back in again. The pipe work up to the airbox is just to allow anything evaporating out of the crank cases to be burnt in the engine.
My old IE did this fake mayo production and my carbie did it too, notice I said did not do.
So all I did was to seal the inlet at the airbox, remove the first condenser chamber and replace it with a little K&N type filter. Instead of having a virtually closed system for the water to flow in and out it vents the vapour. Just ensure that the end is off to one side away from the rear tyre just incase it does spit out oil, then if your crank pressure gets to that level that it's pushing oil up and out then your motors going to be toast anyway.
The crank pressures stay virtually unchanged, remember there is effectively free gas flow from crank to filter in the existing system.

No mayo since.

[Dukedesmo]

I don't have a lot of Monster experience but mine runs at 90 degrees plus when on the move, a few minutes running in the garage saw 135 degrees so I reckon any condensation should clear quickly enough... :rolleyes:

[bobhenry999]

Thanks for that information, really helpful.

i will change the oil and filter tomorrow, and make sure I get it up to temperature in future, hopefully this will be easier once the weather improves.

Thanks again.

Bob

[utopia]

I sense the opportunity for a brainstorming session on crankcase ventilation and oil emulsification, but I have other things to do at the moment.
To be honest, I've never mustered the mental discipline to think the whole thing through from start to finish, but I have blundered about around the edges from time to time.
But just as a starter.......
Lets say that you fire up the monster on a dull spring or autumn day when the humidity is high but air temp is low.
The engine immediately starts sucking and blowing this cool, humid air in and out of its crankcases, through the breather.
The engine heats up progressively, mostly from the heat of combustion, but also from internal friction, sloshing of the oil etc.
The oil circulates and distributes this heat about the engine to some extent, but there are more remote areas which heat up more slowly.
Warm humid vapour in the cases then condenses in these cooler areas within the engine, mostly on internal surfaces of the cases themselves I imagine, and continues to do so until the whole engine is hot enough to prevent this happening.
I'm suggesting here that oil temperature is not in itself a reliable indicator of the presence or absence of these cooler areas.
Of course, if the engine never gets hot enough on a short run, then the condensate is never re-evapourated and expelled through the breather, so it accumulates on each successive short run.
And in this scenario, it seems like the outlet pipe from the breather is just one of many possible areas where condensation may occur in a cool engine.

Humidity obviously comes into the equation somewhere, but I don't have time to check my reasoning on that just now, so I'll say no more (nudge nudge, wink wink......couldn't resist).

How does that sound so far ? ....it does contain some stuff that I've only just considered as I was typing.

On the dommie, which sucks and blows like a bastard, I removed the separator bottle, simply because it was so cluttered around the carb that you couldn't get in there to do any maintenance or tweeking.
It now has a system very similar to the one Nick describes, in that I simply put a length of hose straight off the breather and leading to a small filter (though being a cheapskate, I used a clear plastic fuel filter that I had hanging around).
It still accumulates water in the starter motor gear chamber (above the cases, behind the cylinder....one of the slower areas to heat up, I suspect). In fact I didn't notice it happening before I removed the separator, but I think it probably was.
One thing I was a little concerned about was whether the filter would restrict the crankcase's ability to breathe properly, but I consoled myself with the notion that it was probably more likely to cause a negative pressure in the cases (ie once you'd pumped the air out often enough, the restricting factor is its ability to get back in fast enough, rather than vice versa.....but I'm thinking on the hoof here really) ..and that negative crankcases pressure saps no power and causes no unwanted oil leaks.

On the monster, I removed the pipe from the separator to the airbox and blanked the hole in the airbox, but I left the separator bottle in place.
I just thought the pipe was untidy, I didn't really want the crankcase vapour going into the airbox anyway, and I saw the whole thing as something of a pointless sop to environmental regulations.
I can't quite remember how I dealt with the other end, ie the connection to the separator tank, but if memory serves I put a small u-bend on it, to face it out of the airflow, and stuffed some sort of coarse gauze filter over the end, to keep the spiders out.....I have a look later.

Does any of that shed any light on the issue or prompt any response ?

[jamiedan2009]

I removed the emissions nonsense on mine, still got cream in the window but havent been on a long run for ages, got 200 miles around derbyshire planned for wednesday so will see what happens after that (might cover the oil cooler). I used a bit of the tube from the "emissions nonsense" to give me a 90º angle off the crankcase breather then a length of rubber hose down to the front of the belly pan with a chinese k&n ripoff on the end.

[zhango]

Utopia - I love the detailed analysis but you haven't included piston blow-by. We know that when petrol burns one of the by-products is water so some of that will get past the piston into the crankcase.

The piston rings never seal 100% even when the engine is at operating temperature and the components are at the optimum clearances, so when the engine is cold then everything is far from ideal. This is why starting the engine occasionally during the winter and let it idle without riding the bike in the mistaken belief that circulating a bit of oil is good for the engine is the worst thing to do - once the engine is started then it should be brought to operating temp to achieve optimum running clearances and also evaporate any water in the oil.

Your comment about crankcase breathers:.......and I saw the whole thing as something of a pointless sop to environmental regulations.
Yes!


Dukedesmo - I know you didn't mean to imply that the engine should be idled from cold until the oil temp is 135°C - that was the temp you saw when at idle after a run where the oil temp had reached an ideal 90°C+ so I hope nobody misinterpreted that!
(If I am setting up my fuel injection I have a portable fan like THIS ONE (http://www.machinemart.co.uk/shop/product/details/clarke-18-box-fan?da=1&TC=SRC-fan) from Machine Mart to control engine temp - it works well.)

[Dukedesmo]

Dukedesmo - I know you didn't mean to imply that the engine should be idled from cold until the oil temp is 135°C - that was the temp you saw when at idle after a run where the oil temp had reached an ideal 90°C+ so I hope nobody misinterpreted that!


Indeed, I was being facetious but the point being the temperature it runs at should get rid of any moisture as long as it is run for long enough.

I've not got many miles on the Monster and the engine is 'new' so shouldn't suffer any blow by problems yet but I've had a 916 for 15 years and never noticed any moisture buildup in the oil window. That said I only use it in decent weather and for longish runs so it gets plenty hot enough to burn off any moisture and doesn't get chance to build up like a year round commuter on a 10 mile round trip would... :thumbsup:

[Shuffy]

A solution for the non-techinically minded (like me):

Take your bike for a nice long run and when you get home pop it in your garage/shed/wife's kitchen etc, undo the filler cap and place it on the ignition switch recess (so you don't forget the next time when you start it up) and let the moisture evaporate out over night*. That usually gets rid of it, albeit temporarily, until you do short ride and it mists up again. If that happens repeat the above steps again. Simples!

* Not recommended if you park outside or have foraging squirrels looking for somewhere to drop their nuts etc

[Shuffy]

Apologies to Fireman Sam, who pointed that out already.
(Note to self: Read all the posts before replying...)

[bobhenry999]

Guys,

Here`s an update.

i changed the oil and filter this evening, and then went for a long run.
When I got home, there was still a little mistiness in the window, so I did as "Fireman Sam" suggested and took off the filler cap.
Returned to garage 30 minutes later, and the window is as clear as a bell !

Looks like the problem has been solved, so thanks for all the help.

Bob

[bobhenry999]

Okay, I know this sounds daft as I have posted a thread Re the misty oil window.

BUT, I cant for the life of me see how to list a new posting about another matter, please can somebody help this old and stupid man !

[bobhenry999]

Regarding my last post, I have worked it out !