Oil/gas on my pants leg

[Capt_Curmudgeon]

My ol' 82 R100 has developed a nasty habit over the past couple of years of spraying what I think is mostly oil mixed with some gas onto the the front cuffs of my jeans. Presents itself after about 100 miles and is worse on the port leg than the starboard. Is this a oil breather problem?? I have already performed an air injectomey and the carb doctor at bing agency last maintained the carbs last year. It seems to be getting worse.

Any ideas??

[John Brase]

Capt.

When mine did that it was the pushrod tube seals.

John

[jgr451]

Carb float bowls overflowing?Should do that when sitting as well,though,if the petcocks are open. Can be an intermittent problem.An oil leak that hits the wind should leave a visible trail from your pantlegs back to the source.

[GeoffMiller]

Is the carb bowl sealing properly? On my 82R100, the bowl has loosened very slightly a couple of times. Sprayed my right leg with gas. The wire clip which holds the bowl on must have gotten bumped slightly. Adjust the wire and all is right in the world again!

[Braddog]

Is the carb bowl sealing properly? On my 82R100, the bowl has loosened very slightly a couple of times. Sprayed my right leg with gas. The wire clip which holds the bowl on must have gotten bumped slightly. Adjust the wire and all is right in the world again!

Yep, that's happened to me as well. Now I usually check the clips after I get off to make sure they're where they're supposed to be.

Funny thing is only happened to my "port" side as well. I suppose that's due to action of shifting vs. the action of braking.

[Capt_Curmudgeon]

Good advice about the float bowl and its proximity to that left foot. Have a new pair of Oxtar's and have missed a couple of shifts breaking them in or getting used to them.

Took a long ride this weekend and noticed that there was some indication that the float bowl may have some seepage around the gasket. Wire clip seems to be positioned OK. First chance I get will replace the gasket and maybe lower the gas level a tad. What puzzles me is that there was a drop of what appeared to be oil at the lowest point of the port float bowl exterior as it was sitting on the side stand.

:dunno

[pmdave]

Depending on the year and model, the airbox will trap some oil from the crankcase breather, which can drip out the little rubber valve at the back side. Or, the oil vapor can condense on the air tubes and find its way down to the clamp at the carb intake end. Parked on the centerstand, there is usually a drop of oil on the starboard side. Parked on the sidestand--well you figure it out.

Anyway, the oil can get blown off at speed, and if the carb is leaking that makes up 2-stroke fuel like you have encountered.

My advice (unless you want to do some needed maintenance) is to wear leather pants. That Castrol 20W50 smeared around on leather really makes it shine. However, don't light any matches!

pmdave

[Capt_Curmudgeon]

Dang! I just traded in my leather chaps for high tech ballistic nylon gear.

What maintenance would you recommend? Replace gaskets, adjust float level, ......??

[pmdave]

Har de har! You've been suckered into getting your hands dirty.

There are some common oil leak areas on the airhead, including the valve cover gasket, the pushrod tube seals, and the oil pressure sender. Various rear main seals also leak, but oil drips there go out the bottom, not on your new Aerostich.

So, first clean the bike thoroughly. Get down there with some Gunk and a brush, and scrub off the crud (easterners: "spooge") so you can see what's going on. The pushrod tube seals tend to get brittle with age and start weeping. They just look grotty with the engine off, but at speed, crankcase pressure pushes out some oil. Sorry, the fix is to pull the jug to replace the little buggers. Hey, maybe it's time for a valve job anyway. The pushrod tubes can also get loose in the head. Clean the head/tube area with clutch/brake cleaner, and wick in some high temp Locktite. Or--press in new tubes.

On the R100s, the top of the cylinder head tends to warp with heating/cooling, and the valve cover loses it's perfect contact. I've tried drastic measures such as milling the top of the head, but after a few thousand miles it warps again. My personal fix these days is to use that gray silicone gasket goo to seal the oil in. I glue the valve cover gasket to the cover with some really sticky gasket cement, then apply a thin coat of goo to the gasket surface, and press onto the head gently to see where it's contacting. I fill in the low spots with more gray goo, (carefully wipe up any goo from inside the valve cover to keep it out of the oil supply) and then install the cover partially tight to let the goo set up. An hour later, snug it down gently. "Work fine, last long time".

The oil pressure sender is a simple replacement if it's leaking out the insulator at the connector. If it's weeping at the base, remove, install a new squish ring and retorque.

You can get carb overhaul kits that have all the gaskets. However, alcohol tends to be absorbed by those old foam plastic floats, so they lose boyancy and don't shut off the fuel at the correct level. My choice to install those aftermarket "alcohol proof" bowl/float kits from the Bing man. Pricey, but it solves the problem permanently. While you're at it, change the float needles.

And then synch the carbs. OK?

pmdave

[Capt_Curmudgeon]

Usually you do not have to talk to me too hard into doing maintenance: it is an integral part of the sport and the skills come in handy in a pinch. Like two weeks ago 300 miles from home, two miles up a dirt road in rural Louisiana with a rear tire as flat as a [fill in the blank]. That's another tale of woe and adventure, or misadventure.

Had weeping push rod seals and neutral switch not long ago. A ton of work for not much $ in parts. Roger, that on the valve covers. They are still OK. I really think it is carb related. I have the new float kit and bowl and do not see where any overflow can go except out of a leaky gasket.

Have you used anything other than a cork gasket on the float bowl??

[pmdave]

Earlier, you noted the mixture of gas and oil on your pants. I assumed there was an oil leak somewhere. Could be just gas.

I have used the standard BMW cork carb gaskets for years, and have never had a problem. However, do inspect the surface of the carb and the surface of the bowl for dings and scratches. Best to remove carb, or at least rotate it so you can really see the gasket surface. Could be a bit of cork stuck on there, or a piece of grit, allowing the gasket to leak.

A too-high fuel level in the bowl can cause overflow. Check both valve and level. Since the gasket is normally below fuel level, overflow hints of a level too high.

I have also seen one brass overflow tube in the bowl fracture, with the result of gas weeping off the bottom of the bowl. Remove the bowl, and carefully inspect the tubes for cracking. Or, just swap carb bowls and see if that solves the problem.

pmdave

[Capt_Curmudgeon]

Swapping bowls? Why didn't I think of that? Will give it a shot along with your other advice re: mating surfaces and float level.

Work (that four letter word) will not allow me any time for the next few weeks, but I will let you know how it went when I do get to it.

Thanks much!