Creamy white oil under filler cap

[Scootyman]

Hello all,

Hope everyone is well. I haven’t posted for quite a while. Mainly because my CBF has been SORN for nearly three years as I’ve been so busy with other stuff.

I wonder if anyone has any similar experience to my current findings or any thoughts on what I found today. As I said above, the bike hasn’t been out for around three years. I live in Scotland and my garage gets a little damp and cold in winter. I’ve experienced again today starting problems but having the plugs out for a dry and clean followed by an airline down each cylinder seemed to do the trick of getting the bike started.

Now bear with me on this as there’s seemingly quite a bit to it.

I have an MOT booked for tomorrow so I thought it a good idea to service the bike. I changed the air filter although it didn’t look that bad and replaced both the oil and filter. Upon removing the filler cap I noticed a creamy white substance under the cap. I know what this is, it’s emulsified oil, a mixture of water and oil clearly but why?
I also noticed it was there after changing the oil and running my finger around the inside of the filler hole but I don’t think I’m losing any water as I’ve only topped it up once in the past five years.

I have a few theories on this but I’m unsure if they sound feasible.

Firstly, maybe it’s a build up of condensation in the engine? I tend to run the bike once every three months or so when I charge the battery. It hasn’t actually been out on a run for a long while to get really hot so maybe that’s a thing?

Secondly, maybe it could be the head gasket? When the bike is hard to start it does seem damp in the cylinders which the blast with an airline clears. Of course I don’t know what that is, whether it’s fuel from a flooded engine, water from condensation/water leak  or maybe a mixture of both.

I would appreciate comments on this as many heads are sometimes better than one.
Probably in a few days I will know what it is as if it passes the MOT, I will use it for work for a week or so before I take it to the Highlands for a few days. If the water level drops, I guess that would be a big clue but upon searching head gasket on here, there seems to be very few problems and mine is quite a low mileage example.

As a side note, my chain was putrid to say the least. I’m unsure about using brake and parts cleaner as some do as I’m not sure it’s safe on the O rings so I used half a litre of diesel and a brush. I know Suzuki used to recommend kerosene (paraffin) and I’ve used diesel before with good results. The chain came up really well and has plenty of life left in it for sure so that was a good result.

I also bought a pair of Pirelli Diablo’s from Demon Tweeks for £135 delivered which I will fit in a day or two. I know they are soft and some don’t like them but for me they are ideal with my low mileage. Not old stock either as I had first suspected. Manufactured in week 42 of 2021 so I think I got a bargain.

Any input on the water in the oil would be gratefully received and for the record, I am allowed spanner’s. 
Best regards

[Art]

If I was a gambling man I'd wager it's nothing more than condensation. The most probable cause being running the engine and letting it idle every three months in a damp Scottish garage. It's better to not run the engine. If you want to keep the battery charged during a long lay up remove it, monitor it's level of charge and if it drops to 12.3v or below put it on a 600mA charger for 8 hours, or a 300mA charger for 16 hours. If you want to crank the engine to reposition the likes of the crankshaft, pistons and valve train to minimise any risk of seizing then crank the engine by hand for 3½ or 4½ revolutions via the crankshaft timing sprocket nut found behind the timing hole cap.

If you want absolute peace of mind and proof of the condition of the head gasket then carry out a compression test. I'd replace the spark plugs, brake fluid, clutch fluid, coolant and treat the recent oil and filter change as a flush by running the motorcycle for 1,000 miles and then replacing the engine oil and filter again.

For the future if laying a motorcycle up for 12 months or more change the engine oil and filter on day one of the lay up and again after 1,000 miles of use when putting it back on the road. Used engine oil contains additives that absorb all manner of contaminates, including carbon dioxide and water condensation, over time the additives breakdown and release the absorbed contaminates, carbon dioxide (CO2) and water (H2O) form carbonic acid (H2CO3) which can cause general corrosion, rusting and pitting to steel.

[Scootyman]

Thanks for the reply Art. I was planning to drop the oil again after running it for a week or so. The running of the engine every three months was not so much to charge the battery but to turn the engine over as if I leave it any longer, it’s an absolute pig to get started. I never had that problem when I lived in sunny Hampshire although I hadn’t owned the bike so long when I moved to Scotland. I take your point though and suspected it wasn’t great for it to heat up and then cool without clearing all that rich idling when cold. I shall report back in a week or two the outcome once I’ve put a few miles on.

[jm2]

I do think 'short running' does no good at all in the long term.  You need to get the engine hot or not to bother.
That said, it sounds overdue for an oil change - service guide says annually as the longest interval.

Over winter, just charge the battery up fully before use (as above in the meantime if required) and clear any condensation out with a full 5 second spin on the starter with no fuel input (aka flooded start). Wait 10 and start up as normal.  Worked every time for me, never had my bike not start after winter and ceratinly never needed to take it apart to get it running.

[pedro]

Looking at it logically, assuming that there was no problem when you laid it up, the only possible way that water in any meaningful quantity would find it's way into the engine would be when you start it up and it sucks in damp air. So if you've done that quite a few times, possibly that might cause it. But I still find it hard to understand how that moisture can actually get into the oil. Those of us of a certain age will know that having "mayonnaise" inside the water filler cap in car engines is a sure sign of a head gasket leak, or maybe a cracked head. I know that oil can become contaminated with all sorts and break down, indeed that's why we change the oil. but I have to wonder if so much can infiltrate to cause any significant amount of mayo.

Before doing anything, I'd do as suggested and change the oil again, making sure you got rid of as much mayo as possible. And cross your fingers. If it builds up again, then I would prepare yourself for the worst. But I have been wrong before...

[Scootyman]

Originally Posted by jm2

I do think 'short running' does no good at all in the long term.  You need to get the engine hot or not to bother.
That said, it sounds overdue for an oil change - service guide says annually as the longest interval.

Over winter, just charge the battery up fully before use (as above in the meantime if required) and clear any condensation out with a full 5 second spin on the starter with no fuel input (aka flooded start). Wait 10 and start up as normal.  Worked every time for me, never had my bike not start after winter and ceratinly never needed to take it apart to get it running.

Whilst I appreciate your reply, I have changed the oil every year despite the lack of use and this was the first time I noticed the creamy substance under the cap (because it wasn’t there before).
I have also tried as you have mentioned, the flooded start procedure to clear any condensation etc from the cylinders but with mine it doesn’t work. That’s the reason I have needed to dig a little deeper with diagnosing the starting problem and find a cure. It’s funny because now I’ve been to the testing station and given it a run, it seems happy to start on the button.
I also checked the oil cap and the creamy substance has now disappeared. So probably my garage was damper inside than I first thought. Saying that, my milling machine table and the steel sheet work surface I have installed on my bench hasn’t corroded so it cannot be that damp in there. I guess I’ll keep an eye on it from now on.

[Scootyman]

Originally Posted by pedro

Looking at it logically, assuming that there was no problem when you laid it up, the only possible way that water in any meaningful quantity would find it's way into the engine would be when you start it up and it sucks in damp air. So if you've done that quite a few times, possibly that might cause it. But I still find it hard to understand how that moisture can actually get into the oil. Those of us of a certain age will know that having "mayonnaise" inside the water filler cap in car engines is a sure sign of a head gasket leak, or maybe a cracked head. I know that oil can become contaminated with all sorts and break down, indeed that's why we change the oil. but I have to wonder if so much can infiltrate to cause any significant amount of mayo.

Before doing anything, I'd do as suggested and change the oil again, making sure you got rid of as much mayo as possible. And cross your fingers. If it builds up again, then I would prepare yourself for the worst. But I have been wrong before...

Agreed Pedro and yes, I understand what the creamy mayonnaise of doom usually means. Fingers crossed it was just condensation 

[jm2]

Not really.  Whilst I've not seen this on bikes, some car engines are notorious for a little mayo by the filler cap; it is all to do with dampness (and quality of oil) and where the filler cap is (on an extender tube for example).

As long as you are using decent oil (and fresh) it is just excess condensation.  But this isn't good, so get the darn thing warmed through and expect this issue to go away.

P.S. Wipe the mayo off though is isn't a good lubricator at the end of the day.

[Art]

Condensation vs water - Short engine runs in winter, especially idling, will cause condensation inside the engine. Add to that a damp Scottish garage environment and you have the perfect recipe to produce condensation inside the engine, it enters via the (damp) air intake and emulsifies with the oil under pressure. On it’s own 'mayonnaise' inside the oil filler cap or camshaft covers is an indication of condensation not a failed cylinder head or head gasket, the assumption here is that the engine oil is black or grey black. If the 'mayonnaise’ is accompanied by brown engine oil that is an indication of water in the engine oil, the more water the lighter the shade of brown until it turns a creamy white. Any suspected fault needs to be proven, in this case by way of an old school compression test, or the more modern simpler method of chemically testing the coolant for the presence of exhaust gasses.

8,000 mile vs an annual oil change – Its all to do with the additives not the oil, the oil will last forever but the additives will breakdown and if left they will turn to a sludge that will restrict or block the oil ways.

[pedro]

Anyway, knowledge is power as they say, so please post the result on here Scootyman. If nothing else, it'll feed our curiosity. Thanks.