Whats causing my oily carbs?

[rob650]

Good Morning, thanks in advance for any advice.

my bike has always had this problem to some degree.  Both my carbs over time will get very oily on the outside bottom of the float housings.  I'm not seeing evidence of oil spraying from the camshaft covers or gaskets.  im having a hard time putting 2+2 together and figuring out the cause.  Any suggestions?

The bike runs fine otherwise - starts easily, idles as it should, gas mileage hasn't changed (40+).  I have changed the fork tube seals and jug gaskets a year ago.  Those areas have stayed dry.

Thanks.

[montmil]

My R65 does not leak oil either, but it does maintain its own refined petroleum patina on the bottom of the engine. I have no good guess as to where it comes from. Corrosion protection.

Is your crankcase oil level stable?

[Rob Valdez 79 R65]

Probably due to the crankcase ventilator that vents into both carburator intakes.

This is why I rerouted mine to atmosphere before the bike was 3 years old.  I have only recently refined the set-up.

My bike was dripping oil onto my left boot!

[rob650]

Montmil - crankcase oil level is stable

Rob Valdez - is the crankcase ventilator system the same as the emissions tubing that runs the underside of the jugs?  I pulled all that stuff off last year and plugged the holes.

[MrRiden]

Oily carbs can be caused by crankcase vent fumes condensing in the plastic tubes that connect your carb to the airbox. Have a look inside the air box to see if you have major oil puddles there. Most likely is is simply just the crankcase fumes causing the oily patina. You can vent your crankcase to the atmosphere but...
you can also make sure that you keep the oil level slightly below the full mark on the dipstick, this may help. The tubing you removed previously was for the air pulse or fresh air system.
rich

[Justin B.]

Rob650, to answer your specific question, NO.

[rob650]

MrRiden you were right on, i have a think film of oil inside the airbox on the bottom and sides.

Is this a problem you just live with, or is re-routing what most people of done like Rob Valdez?

[nhmaf]

If it isn't from a too high oil level, there has got to be another reason why you're getting that much oil blow-by through the breather
hose into the airbox - while it can occasionally happen, it isn't normal.  My '82 doesn't blow any oil up there at all - somehow you are
getting more than normal level of pressure in the crankcase, somehow.   I *used* to know a couple reasons why this could happen, but I'll be damned if I can remember then now......
 

[Rob Valdez 79 R65]

Some people remove the cover of the crankcase breather, and put a piece of coarse steel wool in the small dome.  
This allows the oil mist to collect and drip back down into the crankcase.  (they say)

And don't keep filling your oil to the full mark on the dipstick.
Allow the engine to find it's own level after an oil change.
Add if it falls below half.  Mine runs at 1/2 normally.

[montmil]

Some people remove the cover of the crankcase breather, and put a piece of coarse steel wool in the small dome.  
This allows the oil mist to collect and drip back down into the crankcase.  (they say) .

There are New Age substitutions for steel wool that will not cause harm if a bit is ingested in the engine or gearbox. Try something similar to a Scotchbrite pad or a common kitchen scrub pad.

I build furniture and cabinetry as a sorta-hobby/profession. Using steel wool during the finishing stages can leave trace bits in the wood. The wool will eventually rust -wood maintains a moisture content- and create a rust stain under the finish. Autobody supply stores have synthetic steel wool in grades up to 2000. Great for rubbing out a cabinet finish or a new paint job on our favorite scooters.

[MrRiden]

Rob650,
It would be hard to say if you have a "blow by" problem without knowing just how long it took for the film to build up. Clean stuff up and have a peek every now and then before you decide on venting to the atmosphere. The suggestions of providing some sort of collector ie steel wool or fiber scrubbing pad do have merit. Excessive venting indicates the crankcase may be getting pressurized. Possibly from compression leaking past the piston rings or valve seats / guides. a Compression / leakdown test would give you a better idea. Just clean stuff up first tho and see what ya get. At least thats my guess.
rich

[Bill90Loyale]

The use of engine braking also increase blowby.   Some are able to get substantial relief from the oily mess on the carbs by reversing the hose clamps on the tube-to-carb connection by placing the hose clamp screw on top of the tube rather on the bottom - "sealing" the indented "cuts" in the tube circumfrance.   I'm too tired to explain that any better than the pathetic effort above.   My apologies.

[Rob Valdez 79 R65]

Allow me!

The use of engine braking also increase blowby.   Some are able to get substantial relief from the oily mess on the carbs by reversing the hose clamps [part #1 in diagram] on the tube-to-carb connection by placing the hose clamp screw on top of the tube rather on the bottom - "sealing" the indented "cuts" in the tube circumfrance.   I'm too tired to explain that any better than the pathetic effort above.   My apologies.

[Semper Gumby]

Montmil - crankcase oil level is stable

Rob Valdez - is the crankcase ventilator system the same as the emissions tubing that runs the underside of the jugs?  I pulled all that stuff off last year and plugged the holes.

Very little oil can go a LOOOONG way!