Mayonnaise

Maestro, SEI-V

Re: Mayonnaise

Postby penman » 25 Apr 2017 12:57

Yes, I'm embarrassed! I think I had a cursory look, not expecting to see anything. This time, as I say, I pulled the pipes off and had a good look inside. I am somewhat relieved now and I'm beginning to think that this is probably a common issue with this breather arrangement. If you aren't looking for it of course you won't notice, especially if you have non-transparent breather pipes.

I assume that the collector box has internal baffles, equivalent to the labyrinth thingy which goes in the earlier breather pipe, of course I don't know that for sure, but the parts book doesn't show any baffle or labyrinth in the pipe. I believe (someone correct me if I'm wrong) that the breathing system needs a bit of back pressure on the big crankcase breather to ensure that oil mist is driven up to the rockers and presumably the collector box provides this. I may try putting the labyrinth in the short pipe from the crankcase to the collector box as well as disconnecting the air box pipes.

I think the reason the oil goes a bit sludgy is that this emulsion fills the collector box and then tends to slip down the pipe into the crankcase.

This all needs a bit of thought, I really don't want to start devising a water trap, the breathing is complicated enough as it is!

Regards,
Joe.
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1975 Triumph T160 Trident
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Re: Mayonnaise

Postby Ming » 25 Apr 2017 15:31

penman wrote:... I believe (someone correct me if I'm wrong) that the breathing system needs a bit of back pressure on the big crankcase breather to ensure that oil mist is driven up to the rockers ...


I have always understood that the oil mist system requires the baffle in the crank-case breather, plus the two labyrinths in the rocker boxes, in order to to provide back pressure for the oil-mist system 'up top' to work properly. I'm pretty sure that the New York that was briefly in my possession had baffles in the crank-case breather, plus the collector box, which only had baffles to guide any oil / moisture to the drain line.
I have been known to be wrong, though... :?
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Re: Mayonnaise

Postby penman » 25 Apr 2017 16:31

I cleaned this all out again this afternoon, I'm getting quite quick at it now! Poking about with a bit of wire through the various ports of the collector box, I think each of the 4 small pipes has its own compartment, separated by vertical "walls". The larger port for the crankcase breather tapers towards the top and I think there is a hole connecting it to a larger compartment, approx half the volume of the whole collector box. I think all 5 compartments are linked by small holes at the bottom, which will allow any oil (or water!) to drain back into the crankcase. If I had a spare one I'd be tempted to take a hacksaw to it to find out for sure what goes on in there!

I have put everything back as normal except that I've put one of the plastic baffles / labyrinths in the rankcase breather pipe as well. I'll be surprised if this makes any difference but we'll see. I haven't yet disconnected the breathers from the airbox in the interest of making just one change at a time. Unfortunately I didn't have time to go for a test run today.
1980 Moto Guzzi V50 II
1978 Triumph T140 E Bonneville
1975 Triumph T160 Trident
2014 BMW F800GT
1978 Morini 500
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Re: Mayonnaise

Postby norbert » 25 Apr 2017 16:57

I´m struggeling as well a bit with the breathing system of my new bike Dulcinea (but without mayonaise problems).

Rocinante (501 K) wears the old system, an odd plastic tube that originaly ends under the seat, which I prolonged to the rear end of the frame. I put inside only one of the originally two baffles and it works fine for many years like that. The tubes of the rocker cases ending to free atmosphere somewhere underneath the motor.

Dulcineas crankcase breathing system is a bit different because the rear exhaust pipe that does not allow a straight upward breathing tube. I´ve put a somehow sofisticated metal tube with 10 mm diameter (inside) thet leads to an old oilcan. In this oilcan I´ve put a ventilacion tube to atmospere of only 5 mm. This is obviosly to small, oil coming out from the clutch, behind the generator and pickup. I´m going to give it a bigger ventilacion tube of 15 mm. The 10 mm tube from the crankcase to the oilcan has no baffle inside. My calculacion was that the 10 mm diameter would give more or less the same passage as the original baffles (original breather tube is 18 mm). The metal breather tubes of the Enduros have about 15 mm without baffles inside leading to the breather box. I hope with the bigger tube on the oilcan the system will work. I´m gonna see it, when I ride to the danish meeting at Sören 5-7 of may :wink:

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The mayonaise problem of penman I really don´t understand. Where does this water come from after changin the oil several times? :roll:

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Re: Mayonnaise

Postby 72degrees » 25 Apr 2017 18:15

It would be interesting to perform a dissection on a collector/breather box. I think the labyrinth baffles provide a large surface area and perhaps some reduction in gas velocity without creating as much back pressure as a smaller diameter plain pipe. I'd say you definitely need a larger outlet for a catch tank. For 'racing' I route my rocker box and crankcase breather (with two baffles) tubes in to an old plastic oil bottle stashed under the seat behind the left hand side panel. The gap around the gathered tubes where they enter the bottle gives an effective ventilation area of far more than 5mm or even perhaps 15mm.

Mind you, I haven't checked it since I rigged it up to see if it needs emptying. Then with a newly re-bored engine I'd sincerely hope not! The tubes are all clear plastic and there's no sign of mayonnaise. Not on the 375 that has done a fair few miles either.
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Re: Mayonnaise

Postby 'It must be a .....' » 25 Apr 2017 18:36

Hi, in all the 500 Morinis, both road and Camels there is nothing (NO labyrinth baffle) in the pipe from the rear crankcase to the bottom of the breather collector box.

Time to vent to atmosphere and go for that long run? Good luck
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Re: Mayonnaise

Postby norbert » 25 Apr 2017 21:53

Without the oilcan, only with the 10 mm tube it was only the clutch that was loosing oil. The motor is new to me, so don´t know if its leeking over there anyhow. And I´m not sure yet about the compresion rate. But you may be right that the tube should be wider. I thought about it the same way, the labyrinth rises the presure only for a few cm. But this one was easier to bend, it´s from underneath a washbasin, cromed copper, so I´ve decided to test it. I´ve tried to bend a normal size plastic pipe but could not do it propperly with the angle that I need. I hope that it´ll work with the definitive new rebuild motor that will be mounted after the danish meeting. If not, I´m gonna modify a endurotube. Will keep you informed :wink:

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Re: Mayonnaise

Postby Ming » 26 Apr 2017 07:19

Hello Norbert - you could make up a pipe from plumber's copper pipe and connectors (90deg, various angles, straight), certainly in 15mm and I think in 18mm. Would polish up well, too!

I made a filler tube for my engines that way, beats trying to pour oil half way across the engine. :wink:
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Re: Mayonnaise

Postby 3potjohn » 30 May 2017 19:03

I get mayonnaise on my 350, even after a ride of 700 miles one weekend and about 400 a of weeks ago all including a non stop of 120 miles each way. I changed the oil and I,ll swear I could see a small globule of water in it.I tried re routing the main breather as surely water can only get in via this route of from combustion. it cannot be doing big ends much good I would think. I do not squirt water at the bike when washing it either. it burns no oil nor smokes and is doing loads of mpg all a bit odd.
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Re: Mayonnaise

Postby penman » 08 Jun 2017 09:37

Apologies, I have taken my eye off this discussion which I started! For me the present situation is unchanged. I get mayonnaise all the time on the 500. Not surprisingly it is better on long runs and worse on local pottering about, but I'd say it's always there. The bike is currently off the road while I attend to some cosmetic jobs and I've managed to distract myself with another project. I seem incapable of finishing one project before starting the next!

The 350K2 produces less mayonnaise but it does still make some, but in that case a long run tends to clear any mayonnaise, leaving the breathers pretty well clear. I am tempted to ignore it now, I think this is just a by-product of this breathing system. Both bikes have excellent compression, they don't burn oil and both return 65+ mpg and run sweetly. If I didn't have transparent breathers I wouldn't know about the mayonnaise! Hmm, I think I've some black tubing somewhere......
1980 Moto Guzzi V50 II
1978 Triumph T140 E Bonneville
1975 Triumph T160 Trident
2014 BMW F800GT
1978 Morini 500
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