Crankcase breather leak

[tripodtiger]

 
I reckon I've sussed out the source of the oil...

When I first saw the pool of oil on the floor I checked it and it looked clean.  Didn't give that much thought because I'd done gearboxl & middle gear oil changes.  It did sit on the finger tip and it looked really clean.  That should've been a tip.

I am now using an oiled foam UniFilter.
 

Is this an example of 'catastophism'?

I should've known.  The airbox on my 690 always had a small amount of oil on the bottom.  There is no way known that I can get the foam fully oiled without gravity dragging some of it out.  On the 690 it just sat there.  On the XS, it drains out the bottom.

And, after several years, I think I've worked out why the front brake lever on my TLS brake of the RD never pulls back completely when I release it.  I reckon the cable inner is actually a mm or 2 too long.  Yet another   

At least I didn't spend money on trying to work out these 'problems'.

[tripodtiger]

Thanks, blokes.

I don't suspect I've overfilled the oil.  Novice error that would be.   
Then again..
I never considered cleaning the breather to the airbox.  After 31 years, it may be a job.
Maybe it's got insects.
I've found a mouse in the airbox, but that was many years ago.

I could not find two words on the breather in my manuals.  I had to go to Bike Bandit to actually confirm that it was a breather.

getaroundtuiut

[Clutch]

sounds like you might mean the middle gear breather, small right angle fitting with about a 3-4mm hose attached which is routed down? either way first thing is to check oil levels. did once have oil blowing out the c/case breather but that's what happens when you check oil level at night with a dirty sight glass.

[Eveready1100]

Ray, have a look inside your airbox. if there's that much oil leaking from the breather cover, it should have left evidence inside there. If there isn't a lot of oily residue inside, maybe the breather hose or airbox fittings are clogged which would make the crankcases pressurise and leak oil out wherever it can. A bit of blowby is normal once you get some miles on these motors. Usually, the breather setup will dispose of the fumes through the motor without any outside evidence like smoke, so try the easy checks before any surgery.

[excess.11]

Ray.............Pressure build up in the crankcase usually turns your oil into a frothy mix as you ve described .............finding out where the pressure is coming from will be the challenge.Check your compression for blow-by.

http://www.bobistheoilguy.com/blowby.html

http://www.aa1car.com/library/engine_blowby.htm

Also check you have nt overfilled  your oil...........a simple but easy mistake depending on how clear your sight glass is.The breather seems to be doing it s job by alleviating pressure build up.
Good luck ............

[tripodtiger]

The crankcase breather, on top of the cases at the rear and positioned between the middle gear case and the flat breather cover, is leaking fairly significantly.  Not a lot of oil, just a lot of mess and cause for concern.

Any ideas why oil would be blowing up through the breather?

How about repair?  Just simply replace the breather, making the first assumption that it's the breather that has actually failed?

And if the breather hasn't failed, what should I be considering?

Not too long ago I took the breather cover off, thinking that was the source of the leak, but there was no, nil, nothing oily visible.