Breather Pipe Issue Cali 2

Some knowhow and advice needed here, as my Cali 2 1000 pulled a bit of a stunt on me last night. In the doubtless universal fashion, locked-down as we all are, I went to the Cali and started her up, which she did on the button. The bike warmed for a couple of minutes and then sat ticking over very nicely. At this point, I noticed a large pool of oil forming underneath. A very large pool. Investigations today reveal that the oil had pooled heavily on top of the gearbox, and as far as I can determine it has come from the breather tube which runs between the top rail of the frame and the air box. Unfortunately, I cannot state for certain whether the tube had come adrift from the airbox or not, as I removed the box before being able to check. I did notice that the stubs into which both tubes locate on the box were split, so making them very loose. The large breather tube between the top of the crankcase and the frame top tube appears intact and properly connected. The oil, from colour and smell, is engine oil. So my obvious question is, why did this happen? Any and all suggestions gratefully received…

Rocker feed split I reckon,
it runs from the top of the crank case, (just behind timing chest cover) up and out to both heads, when it goes the oil gets everywhere.

Rocker feed would be the first place to look.
If not there, then your crank breather could be blocked. There is a large ball bearing that sits in the vent on top of the bell housing and acts as a one way valve. If this sticks shut, then oil is pumped out of the smaller return pipe that goes to the bottom of the crankcase.
That is assuming the vent system on the cali 2 is the same as the earlier Spada T3 type models.

Thanks for your replies. I have checked the rocker box feeds, and there’s no sign of any problem there. The small pipe which comes from the frame top rail actually runs to the air box in between the carbs. Just underneath where this pipe goes into the air box is where the oil is deposited. I’ve had the large breather pipe off, ball bearing valve seems to be free and ok. Struggling to come up with an obvious answer.

Rocker box gasket leaking?

You’re going to have to clean everything down and track it back to find the source. It sounds like you have looked into the air box, they can fill with oil on some models, generally associated with breather problems.
What have you done to the bike recently? Have you topped it up or changed the oil?
I would replace the split pipes and see if the box will glue back together (after a good clean and degrease) or see if Gutsibits have a replacement.
Maybe the oil has been collecting in the pipes for a long time and emptied out as the pipes split?

Don, what you say makes sense. I haven’t done anything to the bike in terms of oil changes etc - this was a bit out of the blue. But if this is something that has been waiting to happen with pipes about to come asunder, then you may well have hit on the cause. I’ll check and clean everything and stick it carefully back together. Then start her up and watch very carefully…

Presume it has the drain tube back to the sump, if that’s blocked it can’t go back into the sump from the breather oil catcher, so that fills up and it drains onto the floor instead. Like Don said needs all taking apart for a good coat of looking at; check the smaller drain tube or hose that goes back to the sump is clear, you can simply blow some air (gently!) into it with a foot pump of similar, if it’s clear you should hear the sump oil bubbling. If like the other Tonti models the metal pipe in the bell housing connects to the sump pipe using a hollow banjo bolt, which means very small holes in that item.