Carburetor Goo

[ddebonis]

Howdy-

I have noticed a goo dripping from from the connection between the snorkel and the carb. It feels like oil, does not smell like gas... but could it be oil? Or might it be some residue from gasoline?

All ideas welcome... And what to do about it? Perhaps a fuel line cleaning additive or gasoline stabilizer?

-Danny

[Burt]

I would check the collector box above the inlet duct for a pool of oil.  Possibly the engine is being pressurised via an internal leak (?), with oil atomising through the crankcase breather, cooling and then pooling there.  The collector box breather may be gummed up not allowing this oil to drain out.  

I would guess the bike is parked on the side stand and this is the left inlet duct.  

Just an idea.  

Burt.  

[bruce_launceston]

The crankcase breather tubes vent into the air intakes. It's common for oil from the crankcase breather to make its way out of the carb air intake tubes and drip onto the foot levers, the solution is to turn the clamps 180 degrees so that the screw adjuster is at the top instead of underneath the tube.

It's a simple but effective fix.

[montmil]

Confirm left or right carburetor.

Is bike parked on sidestand or centerstand?

Have you removed the air filter and inspected the air box interior?

At what level to you maintain the crankcase oil?

[Barry]

As has already been said it's a common enough occurrence. Remove the plastic inlet elbow and check that the breather tube is reasonably central in the tract which will give the best chance of the oil mist being carried through the carbs as vapour rather than dribbling down the inside of the elbow. We suspect the left carb gets more breather mist than the right but there is no logical explanation as to why that should be. Excessive amounts of oil coming out the engine breather may be due to other issues like a defective breather valve, excessive piston blow by or often just too much oil in the sump. Most airheads run with a max. oil level of half way mark on the dipstick for that reason. It may initially sound unreasonable that you should have to do that but it was in fact an official BMW recommendation.

If you have had a lot of goo going through the carbs and they haven't been cleaned/overhauled for some time it might pay to check the area around the needle jet emulsion tube which is where this stuff can collect and block the needle jet pre-mix air flow. Easy enough job as long as nothing is seized. Just drop the float bowls, unscrew the main jet and the jet holder. The needle jet and emulsion tube should fall out in that order.  For me this should be an annual check every spring especially if you ride through the winter in very cold temperatures.

[ddebonis]

I keep the bike on the center stand.
This issue is happening more on the left side.
I believe the oil was last changed within a year, less than ~2k miles ago.
The oil is topped off - comes to max on dip stick.
I have not yet inspected the airbox.

Stupid question: what do crankcase breather tubes look like?

Thanks everyone.

[Bob_Roller]

There's another thread in this section about oil in the carbs .
it's under the heading R65LS 1982 Carb Leak .

At the end of the thread, there's a few pictures of the air box, this is from a second generation R65, I don't know if you have the 'clam shell' air box or the latr version .

But it gives you an idea of what the ventilation tubing looks like .

[montmil]

MotoDe should have the later airbox on his '84 R65.

[Bob_Roller]

I missed the year of the bike by the avatar !!!!

[Burt]

MDB, the crankcase breather to me is the rubber hose/tube or vent hose that runs from the top of the engine casing into the air box.  

Different folks call things different names depending on which part of the planet you landed on.  But then again you northern hemisphere chaps are all upside down anyway.  

[Barry]

I would consider dropping the oil level to the half full mark. Just about every airhead who is aware of the issue does this. BMW avoided an absolutely direct  instruction to run below the full mark but advise in a service bulletin "not to add oil until the level reaches the minimum mark" and "add no more than 1 pint" and "too much oil results in high oil consumption via the crankcase breather". Adding 1 US pint from the miniumum mark would get you to the half full mark or perhaps a touch above. It's pretty obvious from those comments that they were aware that high levels resulted in excessive oil mist coming out the breather.

[MrRiden]

Your Breather tube, between the top of the engine and the air box, should look something like this. Remove it and stuff a bit of copper scouring pad into the end closest to the engine. It will give the oil vapor something to condense on and drip back into the engine. Clean out the air box and lower your oil level to halfway to the full mark. Done. Some fuel additives have been reported by others to play havoc with the rubber diaphragm in your CV carbs and are not recommended. YMMV.
http://i101.photobucket.com/albums/m70/mrridden/11430.jpg