Hitchcocks Forum

My Bullet (500 classic) has been running lovely lately, so I just thought I'd check the oil level.


When I unscrewed the oil cap I discovered that off-white mayonaise like substance, that reminded me so much of having British Leyland cars which regarded head gaskets as consumables.


Clearly some water has got into the oil. But from where? How much? Is this evidence of a wee bit of condensation in the oil and nothing to worry about, or a full on disaster that should not be started under any circumstances.


Confused...

Hello driverchris ----- I run a 2005 Classic 500 which has just had a full top-end overhaul and new piston etc. ----has 7,000 on the clock and does that as well. You've got a big mass of Aluminium ( Especially the 2 rocker covers directly over the hot head !!) and all night for it to cool down. Do you have the breather mod. fitted ??  I used to be in the automotive trade and yes, that "frothy-coffee" in the water header tank was a sure sign of a big job coming up. I don't think there's much you can do about it really. Longer rides are better than the short commuter run for any vehicle---gets the engine up to running temp.  Whenever I check the oil level I usually wrap a bit of cloth around a long, screwdriver and clean as much as I can out of the filler neck. By the way---- I had to smile a little at your opening sentence-----on the reverse side of that statement are you saying you don't check the oil level when the bike is running rough ?? LoL !! Only joking, matey. Best regards to you------- watch out!! here comes the others---- Bye 4 now

Mayo is no problem IMO. It's only emulsified oil, heat some up and the water evaporates leaving just the oil.


The way the engine breathes doesn't help, in most cars there is a vacuum connection to draw out crankcase gasses, on the Enfield there is only the duck bill to spit out any pressure. The breather mod is good in that it will stop oil loss, but it makes no difference to breathing.


As long as the oil is changed at normal frequencies no harm will be done. I'm not sure that longer rides will clear it as once the moisture in in there it can't get out whatever temperature the oil gets to.


 

Do you still have the catch can connected? You should find it behind the battery box. There is a hose from the crank case on the left side to the catch can and a second hose usually goes back into the casing on the timing gear side. This allows a one way flow of crankcase gases, but traps moisture / Mayo.


The catch can should be moved every few thousand miles and cleaned out. 


One regular mod was to remove the hose that goes back to the timing side and turn it to blow over the chain, but first fitting a duck bill over th end. The vapour then helps to lubricate the chain. Mayo is a product of combustion where exhast gas escapes into the crankcase and is very moist. The oil tank runs much lower than engine temperature, typically between 50 and 60 degrees C. This is not hot enough to evaporate the moisure, except if you have made a long run in quite warm weather. Mayo is not damaging and is hard to eliminate in this engine.

Hi driverchris. Funnily enough I've just been checking the oil on my own Classic 500 and noticed the same thing all around the filler cap. My Triumphs and BSAs from the 70s used to do the same thing, and like the others on here have said there's not much you can do about it. I was always told that a gallon of fuel under combustion produces a gallon of water, most of which get burned off as vapour in the process. On short runs or in cold weather some of this vapour mixes with the oil and produces the mayonaise. Hmmm, well that's what I was told!


Riggers.

thanks for all the responses guys, very reassuring

Have a read of this.


http://www.whfolk.co.uk/REOCHUMBER/Arti ... eather.htm

Bullet engine oil is always too cool, even in sub-tropical Queensland, mine seldom reaches 60C on the hottest-longest runs. Put a thermometer into the oil after a run, it will probably show 50c; most engines run oil around 80c at least.

I have two Classic 500's. The one from 2000 has never produced mayo.... either before I fitted a duckbill or since.


The year 2007 bike, same engine, has always produced mayo. It has a chair attached, so is obviously pulling more weight.


One difference is that the 2007 bike has two rubber tubes to the catch can. Any thoughts as to whether I could use two duckbills on this, to save emptying the can?


Or does the can in some way balance the pressure of the 2 tubes, and needs to be left connected?


Regards, Chris

I do not normally go in for turd polishing but I did after some thought decide that the Breather modification might be a good thing.


Fitted it to our 1994 Bullet 500 and promptly got emulsified oil (mayo) in the extended filler neck and rust inside the filler cap.


Now back to standard breather & no more mayo.