Sight Glass/Oil Level

["Tom Brown" <tbrown@xxxxxxxxxxx>]

Dan:

>What's the mystery on the accuracy of the level glass on the 12GS? I find
that the levels vary so much from start to start. The problem is that some
days I'll stop the bike and it needs 250ml. Next day it's a bit over the top
of the sight glass; day after it's at 3/4s, etc.
time I top it off. I'm just trying to do so with a modicum of accuracy.

>Anyway, is there anyone out there with a better metal picture than I about
how the BMW crankcase area set up, etc such that they can explain this
migration of oil?


This question comes up once or twice a year on this list.

I've found that the oil coolers on the 1200s are actually better than the
older bikes as far as not holding oil.   The readings are actually a little
more consistent.

1. First thing I'd do is read the Rider's Manual.   They have a pretty good
procedure.

2:  Remember that the bike has to be FULLY warm when you shut it off.   Not
just a mile or two of riding and not just warm oil...fully warm engine.

3:  Edelweiss just puts the bikes on the center stand at night and tops them
up in the morning.   I imagine they overfill some bikes now and then, but
that's their system.  They take care of about 120 bikes and don't seem to have
a problem.  I didn't check their airboxes for oil, but I'm sure there is some.
This is the procedure that BMW recommends too....although they think the oil
should be at operating temp when checked, not cold.  If you check with a cold
bike, know that the reading

4:  What I do is put the bike on the side stand at night.  Next day, I put it
on the center stand, wait about a minute and check the level.   If it shows no
oil and I feel that's not right, I'll top it up only to the bottom of the red
ring on the site glass...no more.  That way, if more oil magically appears on
the next oil check, It'll be about 3/4 up and not overfilled.

5:   The airbox has a DRAIN PLUG.   It's a bayonet type plug.  Just turn it
1/2 turn with your hand and remove it.  You locate this under the bike on the
outside bottom of the box not far from the rear wheel.   Checking the breather
pipe is not what we mean.    Don't remove the breather pipe.   If you're
really filling the bike properly, the bottom of the airbox will be dry and the
plug will be dry.  If you're grossly overfilling you'll have a good bit of oil
spill out when you removed the airbox plug and will probably have seals on the
block lightly seeping oil.  This isn't the end of the world and probalby won't
hurt much, but we like things neat around here!

 6:  If you're going on a long trip with a new bike, you should carry a quart
of oil.   I have bag liners and put my oil in the lid of the system case
outside the liner.   I put the quart plastic bottle in a zip lock Glad bag and
put an oil hand towel around that to keep vibes from ripping the bag.

7:  Don't use synthetic oil in these bikes until 12,000 or 18,000 miles.   If
you wanted to wait for 24,000 miles, I wouldn't  scold you.   If you change to
synthetic before it has stopped using any more than a very small amount of
oil, you're not likely to improve oil consumption any more.   Synthetic is
just too slick to allow much additional ring sealing to go on.

8. The oil that's being used by the engine is slipping by the rings and valve
guides and blowing out the exhaust.   The fit of piston rings is extremely
precise.  The method BMW uses on their bikes is to get the rings close, then
put a special oil in for the first 600 miles of riding that allows the rings
to be "cut" or shaped to the cylinder walls' exact size.   Depending on the
amount of material that needs to be removed, it may be completely successful
or it may take more time.   The cylinder walls are made of extremely hard
material similar to "Nikasil" once used in race engines and then in Porsche
engines. I think BMW has their own process now.   Anyway the two surfaces have
to mate together with the softer one forming to the harder one.   Once this is
done, oil consumption goes down and the bike runs better.   Only after this
should you start using synthetic oil.   Synthetic oil is really good for
oilheads because a) Oilheads don't have wet clutches, which generally behave
badly when bathed in pure synthetic.   b) The oil running through the oil
cooler can build up a coke like deposit on the walls of the oil lines and
inside of the cooler, especially when oil temps get high.  Synthetic doesn't
do this and will actually clean them up over time maintaining good cooling for
the life of the bike.

9:  Interesting thing, BMW cars use a very expensive synthetic oil from the
start and have extremely long oil change intervals.  They do not use ANY oil.
Shape of things to come?

- -TB

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