Oil being forced from breather

[limeyrob]

And to add that having had an engine with stuck and broke rings they are very hard to start and smoke horrendously so I agree, this is not likely.  Is it a possibility that the oil came out the tank overflow?  Does that have a pipe on it to anywhere?  But you say its happened several times so I'm clutching at straws.

[Andy Williams]

Hi no oil change (well planed anyway!) since getting the bike back however have had to top up due to the amount of oil loss, (topped up after having the sump off to drain any contents).
Have always used this oil so cant see that this would be an issue?
Think a lot more reading and trials seems to be the order of the day. 

[chaterlea25]

Hi Andy,
Pull the timing cover and check the breather sleeve cork washer
There should be no end play on the top hat breather, even a small amount can cause your problem.
It should be possible to rotate the top hat a
little on its drive peg , but it should have some resistance.

Is the SRM sump plate fitted so the magnetic plug is as far away as possible from the pickup tube?
I had a problem on a bike where the magnet stuck the ball closed
Unlikely in your case but you never know

John

[Jules]

when the magneto was refitted was the cork washer (re)fitted????

[Andy Williams]

Again very many thanks, but is the Cork washer not behind the inner timing cover and as such would not have to be disturbed during the magneto installation?
For information the SRM sump plate has been on the bike since i have owned it about 5 years and has not been a problem but you never know?
I must say that it does seem a massive coincidence that the problem only started post the mag work?
 

[RichardL]

Andy,

Is the oil release from the breather port profuse or spattery? The couple of times I’ve sent oil through the breather, due to wet sumping, the flow was profuse, leaving a puddle under the bike. Until now, I haven’t thought that much about the mechanism for this, but the basic element has to be the magneto/breather side of the timing cover filling with oil. How (I ask myself)? I believe it must be that the flooded crankcase is causing the timing gear chain to bring up more oil than can be drained from the breather side after being flung from the magneto gear.  Regardless of whether this idea is correct for wet sumping, it seems profuse flow with no wet sumping still requires the breather side of the cover to be flooded.  This would make me want to check for obstruction of the drain hole at the bottom of that compartment.  Now, back to Chaterlea John’s point about the cork gasket, I “think” (not “believe”) that a bad cork gasket would result in spattering rather than profuse flow from the breather port.


Looking forward to any challenging Chaterlea chastisement if necessary.

Richard L.

[Andy Williams]

Many thanks Richard I would describe the oil loss as somewhere in between profuse and spattery the flow is fast enough to provide a fairly constant drip resulting in a small pool of oil in a very short space of time!
think i will be removing the timing cover after work today!

[RichardL]

Another possibility just popped into my head (plenty of vacancy available for new tenants). If the pocket in the timing cover for the timed breather has been packed with grease, leakage due to the cork gasket could not drain. All this is amongst my quandary over the effects of the reducing disc in the throat if the breather. Maybe that disc allows leakage from the cork to accumulate for a faster outflow.

Richard L.


P.S. Grease in the breather pocket would also mean no breathing, just leaking.

[chaterlea25]

Hi All,
I wrote some time ago about an A10 that took to blowing oil out the breather after an extensive and expensive overhaul.
It eventually transpired that a leak on the end feed block that's attached to the outer timing cover caused oil to be carried up to the breather by the timing gears and onward out through the breather.
I am just wondering if a leak at the oil pump or its gasket could do the same?

John

[Swarfcut]

  Now while the problem arose after magneto work, that's not to say that is the root cause. CJ has a very valid point here, notwithstanding return to the tank indicates the pump is working fine, but a leak here compromises flow to the engine and also give possible scope for a larger than usual return volume. As a first step it is worth taking off the timing cover and checking the security of the pump, and whether or not the keyhole above it back to the sump is clear. The breather bush can be checked for in/out movement....there should be none, and the bush location on the cam gear drive peg checked by observing the bush rotate as the engine is kicked over. Removing the pump to examine involves a fair bit of dismantling, pump drive worm and locking nut are left hand threads. So only tackle as a last resort.

  As a further test, idling the motor over a large catch tray, timing cover off, will show the amount of oil coming from the timing bush, or any leak between the bush and crankcase. This is extremely messy, frightening if you get Niagra Falls, and keep an eye on the rapidly falling oil tank level.

 Swarfy.

[Andy Williams]

Again many thanks to you all, timing cover is off at the moment removed it last night there doesn't appear to be any lateral (horizontal) movement between the cork and the breather there is a small amount of rotational movement. will take the opportunity to check the other areas suggested.
Many thanks 

[limeyrob]

This is baffling me, I've gone to the shed and had a look at an inner timing cover, rotary breather and set of cases.  The only way into the breather is though the hole in the end of the rotating part and this is in the upper rear compartment of the outer timing chest.  There is 1/2" dia cast hole under the breather rotor into the inner timing chest.  The cases have a similar sized hole into the crank chamber about level with this and just forward, level with the idler bush.
For "solid" oil to be getting into the breather the cases would have to be half full which seems very unlikely.  Even if there is a lot of oil around the timing gears it the other side of the inner cover.
One thing I did notice is that the breather passage goes across the cases in front of the camshaft and passes near a drilling down to the camshaft bush.  This has to be re-drilled when a new bush is fitted and a real long shot (very unlikely) is that there is some breach between the breather and cam bush gravity feed.  You could test for this by putting a finger over the breather outlet and blowing in the hole in the inner timing cover, it should be blocked.
The first communication from the inner to the outer chamber where the breather pick up is about 3" up from the bottom of the timing chest so I'm still baffled.

[Andy Williams]

thanks Rob the good new is that my mate who has a vast amount more knowledge than me will have a look at the weekend!
tonight i will be replace the sump, timing cover and rig up an extended breather pipe to the rear of the bike then top up oil ready for dropping it off at the weekend. He is going to go through everything and replace the cork just as a matter of course.
will let you all know the outcome, very many thanks to all who have offered advice.

[KiwiGF]

This is baffling me, I've gone to the shed and had a look at an inner timing cover, rotary breather and set of cases.  The only way into the breather is though the hole in the end of the rotating part and this is in the upper rear compartment of the outer timing chest.  There is 1/2" dia cast hole under the breather rotor into the inner timing chest.  The cases have a similar sized hole into the crank chamber about level with this and just forward, level with the idler bush.
For "solid" oil to be getting into the breather the cases would have to be half full which seems very unlikely.  Even if there is a lot of oil around the timing gears it the other side of the inner cover.
One thing I did notice is that the breather passage goes across the cases in front of the camshaft and passes near a drilling down to the camshaft bush.  This has to be re-drilled when a new bush is fitted and a real long shot (very unlikely) is that there is some breach between the breather and cam bush gravity feed.  You could test for this by putting a finger over the breather outlet and blowing in the hole in the inner timing cover, it should be blocked.
The first communication from the inner to the outer chamber where the breather pick up is about 3" up from the bottom of the timing chest so I'm still baffled.

Not just me then! As my post above, if my bike wet sumps its harder to spin on the kickstart and it might smoke out of the exhaust a bit (but not unless half the oil tank is in the sump) but I don’t get oil out the breather, and I don’t understand why others do experience that, obviously it happens, just why 

So wet sumping doesn’t bother me at all…..no need to get an SRM pump, or drain it before using it….

[Andy Williams]

Hi mate as iv said i don't think my problem is necessarily caused by wet sumping.
Undoubtedly my bike does suffer from wet sumping if left a few weeks without being started she will fire up but im greeted with a brilliant smoke screen that eventually clears as the sump contents get returned to the tank. my recent problem oil being forced from the breather occurs even if the sump has been "manually" drained Pryor to starting and riding??