Dan' Those oil leaks on the outside of the mag cowl are not from the breather,
The wind does funny things with oil leaks,
The breather pipe goes down from that Alloy Hexagon top left.
The oil may be coming out the exhaust pipe , From the lower valve guide in the cylinder head ?,
Or from the the cylinder head joint, Or even from the top of the cylinder head,
Where the oil returns via the rocker feed pipes,
So many things it could be.
Sometimes ?? Vincents wet sump,
After a layoff , Oil drains down inside of the engine ,
Then the owner looks in the oil tank , See's it low and puts more oil in !,
But after starting, The oil pump pumps the extra oil back into the tank and overfills the tank,
Which then leaks out the filler cap all down the sides of the Oil tank / Upper Frame Member ,
All over the engine !.
Sorry, You may know this,
But if we find the engine oil low after a layoff, We drain the sump ,
The sump is called a dry sump, But there is always a small cup full of oil in there !,
The engine drain bung is in a round cutaway in the left " Sitting on the bike ",
Front prop stand holding plate,
It has been known to get a few PINTS out of there !,
So get a big tin underneath.
Normaly you should just see a metal bar about 3 .1/2 " Down the oil tank filler hole,
That's what I use as to the highest I want the oil level to be.