Crank case breather spitting oil

[Danny]

Hi All, I was wondering if anyone could help me out? My Morini has decided to start spitting oil out from the crank case breather. And before anyone asks, I have NOT overfilled it

The details are:
The bike doesn't spit when ticking over
Only starts spitting after 5-10 mins riding
Bike doesn't appear to be down on power
No smoke coming out of the exhausts
Oil also seems to work its way up into the carburetors/air box area

Possible causes which I have come up with:
The pressure release valve is stuck closed?
Piston rings?

That's all I've been able to think of. Does anyone have any suggestions or thoughts on what the problem could be, before I start ripping the bike apart?

Any help with this would be really REALLY appreciated

Cheers,
Danny

[mad muller]

you will get some oil out of the breather, is there a baffle in the breather pipe, if not it wil be more noticable,check plugs are not oiling up, and oil level is not to high, with bike running remove oil filler cap, and look for back pressure my bores were knackerd, and spued oil and smoke from every orifice, even out the headlamp! just rebuilt engine and back in frame , waiting on rings, and valve guides, if its only spitting small amounts i wouldnt worry to much. mad muller.

[3potjohn]

What fill volume do you use?

[Danny]

Thanks for replying.

In response to how much oil was used: that would have been 2.5l, as stated in the workshop manual... which I assume is correct??

The breather pipe does have a baffle in it and the plugs don't appear to be oiling up. Could you please clarify how to look for back pressure once filler cap has been removed? Would I just cover it with my hand, or...??

The amount of oil that is coming out is excessive, in the sense that it's flying all over my back wheel. As much as I love the extra challenge of trying to stay on my bike with a slippery back wheel, I feel it's best to try to remedy the problem

Cheers again,
Danny

[mad muller]

can only speak from my own experiance with my sport, plugs oiling up lookiing wet, when engine was up to temp, smoke billowing out of crankcase breather with pipe removed,excessive smoking from exhaust pipes like a steam train, smell of burning oil, with oil filler cap removed exess back pressure due to worn rings and bore, looked like a boiling kettle and throwing oil out of there as well, all engines have a bit of back pressure , but when its as i desribed its usually ware in the bores rings etc, but you say theres no smoke out the exhaust pipes, and plugs look ok, but throwing oil onto the back wheel is a funnyone, out of crank breather , check its not coming from gearbox oil seal? as i said my engine was shaged due to me thrashing it as it had been laid up for a few years , hope this is of some help.