Originally Posted by More_Miles
Well, I tore into the airbox tonight. Guess what I found?
Oil in the crank case breather tube. Enough that there was a drop or two forming at the end of it. The intake was also oily... I cleaned it all up, and I think I know why the left cylinder was smoking more than the right. The tube that runs from the Tee to the intake was sloped down towards the left. Gravity's a bitch.
I also took the starter cover off. It looks like there has been some oil getting out into this area.
I cleaned it up as best I could, and since I'm almost into the winter cabin fever season, I'll tackle that later. For now, oil is fresh, and I'm going to keep an eye on it. I am pretty sure I know why it's smoking, just need to figure out now why it's blowing oil.
I'm not too surprised cuz that's what I found in my RS (and why I suggested at least looking, back in post 11
). You will
find some oil droplets in the breather tube, as a big twin moves a lot
of air around in the crankcase.
When you get around to it again, check out the internals of the crankcase breather. My '78 RS had the older one, which apparently doesn't work as effectively as the new style. The older one is a fibre washer and a coil spring, while the newer one is like a reed valve. My RS puffed quite a bit of oil when warm, and the new style breather virtually stopped it.
Check an on-line parts fiche (like maxbmwmotorcycles.com) and view section 11, diagram 11_1725. Assembly #2 is the older style, and #3 is the newer replacement part.
If you have the older one, try upgrading to the new one as it's only $30mumble bucks.
If you already have the new style (and the diaphragm is intact) then I'll hush and let somebody more experienced speak up