Oil breather feedback hole

[DeeG]

I finally have time to trouble shoot the oil burning problem with the R45.  Off came the tank and the lid over the starter. found the crankcase breather.  Now comes the hard part.  Where do I find the feedback hole?  Do I need to remove the starter?  Or is it buried under the breather?

[nhmaf]

That round shaped thing with the screw holding down the bent metal plate is the reed valve for the oil breather. Doesn't that rubber hose going into the air breather housing go to a fitting that goes to the cover for the breather?  I'd expect that an oil return galleyway would be underneath it.

[tvrla]

The R65 breather is different than the larger bikes. We've got only one orifice for the breather, the others have two, and I think under the reed valve is the open crankcase. Never looked, but that's my guess.

I think the engineers felt 650ccs wasn't a problem for this engine block and it didn't need anything special like the larger displacement models.

I'm curious if there is a feed-back hole, but I'm guessing there isn't one - just the cavity under the breather valve.

[Barry]

Dee,

You have the replacement reed type breather which is supposed to be better than the original disc. I still have the disc so I'm not sure about orientation as in should the reed point towards the outlet or not ? Yours may be correct. Perhaps someone who has fitted one can confirm.

Even though there is some information about to the effect that all airheads after a certain date have feedback holes, on my R45 the breather is just open to the crankcase and there is no hole.

[DeeG]

Yes, there was a cover on the breather.  It had a hose that had a t-fitting that the other two hoses (you can see a part of one in the bottom left) fit onto.  Those two hoses went into holes (like in the Photo) that opened on the inside of the air filter.  

These hoses were damp with oil.  Filter looked OK. The area under the filter had a bit of oil on it, not too much though.  

So, now that we've determined that it has the new style breather and there is probably no return hole, I'll move on to checking other things.  And tying to figure out how to wire in the aux lights the P.O. installed.

[nhmaf]

As I've also been examining things in this area on my 78 R100/7 (which is apparently quite different, or else is missing something) I found this very helpful weblink --
you won't likely see the oil return hole unless you go down deep looking for it...
http://www.bmwscotter.org/procedures/oil_breather_service/oil_breather_service.htm

[Barry]

That was the information I was referring to in my post above but it didn't help me find the hole.

[nhmaf]

From the website link -

the drain return hole is apparently at the bottom of the "settling chamber" - assuming that your engine case has one ?

[Barry]

I couldn't see any sign of that chamber on mine.  When the breather valve is removed it goes straight down into the crankcase.

If the picture had zoomed out a bit it so we could see exactly where it was supposed to be, it would have been more definitive in settling the question beyond doubt "do R45/R65's have the hole"

We talked about this on another thread 3 years back and I think we concluded that our bikes don't have the hole. http://www.bmwr65.org/cgi-bin/yabb2/YaBB.pl?num=1269278421/1#1


I've got to admit I'm still not 100% certain about our bikes not having drain holes but reading the Scotter's article again If I had to guess I would say only engines with the bottom covers have drain holes and that's not us. It seems to confirm that our crankcases are different.

[DeeG]

I believe the portion of the round hole you see at the top of the photo is the breather hole with the whole thing removed.  On mine, there is no additional hole.  Just the sunken cavity where the starter is, and the one to the rear where the air filter goes.

The breather cover on mine looks like drawing # 2.  P/N 11-15-1-335-756.

I've looked at Bmwscotter and SnowBums page.  I printed out the drawing and sat next tot he bike, trying to match things up. Mine doesn't much look like the drawing (with the oil system highlighted in magenta).  

[Barry]

I believe the portion of the round hole you see at the top of the photo is the breather hole with the whole thing removed.

Yes, that's what I thought but I wasn't certain. I also have the 11-15-1-335-756 cover.

I think we can now say with some confidence there is no drain hole in early R45/R65's.