Actually it is everywhere, breather stub on timing case all the way thru to the tank. Years ago I used to clean the tank every time the rear tab fractured but now that's beefed up the tank only comes off once a year or every 3500 miles. These days I just do the breather and pipework every 500-1000 miles. As I said its usually just water in the catch bottle, this time sludge which I've never seen before. The only difference is that before the last long run I topped up the oil to mid way on the 'correct' dipstick which puts the running level at the return exit. Usually I run a bit lower. That would reduce volume in the tank and whatever crap was building in there might just have been forced out. That doesn't solve root cause but might explain a little different outcome from normal.I re-read the op and it seems that in that oiltank vent catch is where the mayo is, not the engine proper.
I just did that and yes there was a lot of moisture..........If you can't believe there is that much moisture coming out of your crankcase vent then warm up your engine and point the vent hose at a chunk of cold steel or a cold mirror. The water drops will form immediately -just like it does if you hold it behind the tailpipe. Jim
Not mk3 but early 850. Valve is norvil supplied and sits behind side cover fed into tank filler stub and exiting tank to bottle in batt tray. 1/2" to 3/8". Just drained tank which was nasty, lots of gunk, also overfilled which may explain why so much in the catch bottle.Biscuit said:You have MK3 cases and incorporate the original breather stub from the timing side case correct? Pardon my ignorance her but how is the one-way valve and catch bottle incorporated?
rvich said:I battle mayo in my oil. Most of my riding is in a cool climate and the runs are often not over ten miles.
Pleased im not the only one suffering. Dont experience yr consistent low temps though.
No it isn't. I replaced the tank with a good used part many years ago while I was continually fixing the rear tab ( I wanted a spare tank to swop over). I noticed that the return opening was lower than the 'original', probably by 1/2". I also replaced the dipstick with correct 'Commando' part and now run just on the L mark. That's 2.9 litres including filter and lines etc. So in between marks or higher the return is submerged.The oil return pipe in the tank, visible through the filler has two outlets and returns the oil well above the 'HIGH' mark on the dip stick. Is your tank configured this way? Is the vent from the oiltank getting more than just vapor? Just for shits & giggles you could just try a run with out the valve and catch can to see what happens.
Oh yes, plenty of experience on those too! Runs are usually 60-80 miles with regular 120 round trips. It's not only old Brit cars that suffer as my daughters modernish Seat (VW Polo platform) makes lots of Mayo and several winters ago this stuff froze, blocking the breather. So how did it breath? Thru the dipstick, pumping out 2.5 litres of oil in the process. Now, I managed something similar with the Commando by reversing breather valve connections, no effect on running up the motorway at 75mph, pulled off for a comfort break after an hour, parked and looked down for the sidestand, oil everywhere, black on one side from primary mixed with belt dust and clean on the other from wherever it had spewed. It took a stack of Burger King serviettes to clean.Sounds like your rings are worn out or you only do short runs. My experience with British cars in the good old days was they wore out quick and when they did, excessive mayonnaise built up in the tappet covers and where the breather went to the air filter, it blocked the air filter as well. The breather gases usuallyy stank as well. Do yours? You have mentioned doing up the engine, I suggest you do so.