/6 pushrod tubes outside seal

mfp4073 · 05-09-2011, 03:33 PM

Seeing the other thread I figured I would finally post this. I am getting dribbled/sprayed on from my right jug. Right on top of my foot but only when running (does not drip and leave oil on the ground).

its damp under there, replaced valve cover gasket since its right in that area. In looking at the parts sites I dont see an outer seal and also saw it mentioned in the other thread that the outside is possibly interference fit. Also, anyone have a diagram/dissembled pictures. In looking under its hard to tell exactly where the tube terminates.

THANKS!!!

Xcuvator · 05-09-2011, 03:54 PM

Quote:

Originally Posted by mfp4073

Seeing the other thread I figured I would finally post this. I am getting dribbled/sprayed on from my right jug. Right on top of my foot but only when running (does not drip and leave oil on the ground).

its damp under there, replaced valve cover gasket since its right in that area. In looking at the parts sites I dont see an outer seal and also saw it mentioned in the other thread that the outside is possibly interference fit. Also, anyone have a diagram/dissembled pictures. In looking under its hard to tell exactly where the tube terminates.

THANKS!!!

The only way I know of to find the source of a leak is to clean everything up real well, then ride the bike and stop often to see the first signs of oil. I have been fooled before, it doesn't take long for the oil to migrate.

Horsehockey · 05-10-2011, 03:39 AM

As noted above, you should clean the right side of the engine case of oil and dirt. Then spray the area with spray foot powder or baby powder. Then take it for a ride. The powder will expose the source of the leak. My guess is the oil is dripping off the bottom of the right side airtube and/or collecting on the bottom of the float bowl. Oil collects there because your crankcase breather sends oil mist to your right side carb via the tube and some of that oil leaks out at the bottom of the airtube where it mates with the carb. Entirely normal.

mfp4073 · 05-10-2011, 08:04 AM

I promise its not coming from the intake tube/carb. The carb is dry all the time and it would have to travel forward in the air stream to get to my boot. It only happens at speed. There is oil on the bottom fins of the jug. Outboard of the area where the exhaust comes in, but inboard of the valve cover/gasket. Also, the outside of the peg rubber gets some on it too.

mfp4073 · 05-10-2011, 04:57 PM

Picture taken after 10 min of riding. Note its on toe and does not get on pants or uppers of my boots.

Horsehockey · 05-11-2011, 03:05 AM

http://www.discountwholesaleonline.c...med/424598.jpg

Grider Pirate · 05-11-2011, 07:44 AM

Quote:

Originally Posted by mfp4073

Seeing the other thread I figured I would finally post this. I am getting dribbled/sprayed on from my right jug. Right on top of my foot but only when running (does not drip and leave oil on the ground).

its damp under there, replaced valve cover gasket since its right in that area. In looking at the parts sites I dont see an outer seal and also saw it mentioned in the other thread that the outside is possibly interference fit. Also, anyone have a diagram/dissembled pictures. In looking under its hard to tell exactly where the tube terminates.

THANKS!!!

The tubes terminate at the top of the CYLINDER. The oil passage from the cylinder to the head is sealed by the head gasket. The tubes are an interference (tight press) fit into the cylinder.
Whenever I get oil on the toe of my boot, it's the rocker cover gasket. If your rocker covers have been habitually over-tightened by previous owners, they will distort and not seal. Removing the rocker cover and then pulling the studs and checking/resurfacing may help. In my case, the leak is usually caused by using cheap-ass aftermarket rocker cover gaskets.

mfp4073 · 05-11-2011, 09:01 AM

Grider,

Thanks for the reply! Got me some info there I was needing. I dont suspect the rocker/valve cover gasket anymore. I replaced it with a new one and a good one (from huckys, he dont sell cheap crap). Same results. Also, its dry that far outboard.

Took a picture. The wettest part is between the red lines. And again, does not drip when sitting still. So I am thinking its got to be only when there is oil pressure and is not accumulating/dripping. Those interference fit pushrod tubes seem like they could be a culprit if you agree that they terminate in the area shown.

Grider Pirate · 05-11-2011, 11:49 AM

I think that kinda puts it back in the 'other' (pushrod tube in the head) http://www.advrider.com/forums/showthread.php?t=685835
thread area. A couple of the 'old wise ones' have commented that the tube pressed into the head can leak. I have less experience, so I've never seen that happen. I sure can't think of anywhere else your leak could be originating! (Okay, maybe the rocker cover center stud on the head side??? I kinda' don't think that can happen, but.......)

mfp4073 · 05-11-2011, 01:00 PM

yeah, read through that, but since his was a 92 and mine a 74, I was not sure if anything had changed in all those years. I dont suspect the stud since its sandwiched in the gasket.

Hopefully someone with a little more know will drop in. I REALLY DONT want to deal with replacing the tube and the interference fitting aspect. But its messing up my boots and tracking oil in the house.

bmweuro · 05-11-2011, 07:00 PM

Going out on a limb here. On an old Boxer your foot is under the carburetor and the breather hose runs through the right air tube. If it's a high mileage motor maybe it's blow by leaking between the air tube and the carburetor.

mfp4073 · 05-11-2011, 07:07 PM

Quote:

Originally Posted by bmweuro

Going out on a limb here. On an old Boxer your foot is under the carburetor and the breather hose runs through the right air tube. If it's a high mileage motor maybe it's blow by leaking between the air tube and the carburetor.

Good thought, but that area is dry. Furthermore a leak at the carb or the carb mounts (rubber heater hose) would all be vacuum leaks, not blow out.

bmweuro · 05-11-2011, 07:21 PM

Quote:

Originally Posted by mfp4073

Good thought, but that area is dry. Furthermore a leak at the carb or the carb mounts (rubber heater hose) would all be vacuum leaks, not blow out.

Nope. You have a breather hose that vents the crank case and goes right into to air tube pre carburetor vacuum.

mfp4073 · 05-11-2011, 07:37 PM

Quote:

Originally Posted by bmweuro

Nope. You have a breather hose that vents the crank case and goes right into to air tube pre carburetor vacuum.

The vacuum of the motor drawing the air in goes all the way to the air cleaner. The crank vent does not pressurize one side....unless I am getting so much blowby to create a supercharger effect! Its a scavanging effect of the motor pulling fresh air in and pulling vapor from the crank case with it. Unless BMWs are very different from everything else I have ever worked on......well let me take that back....

bmweuro · 05-11-2011, 08:00 PM

To rule all of this out pull the air tube and clean it out really well. Put it back on the bike and see if your still get oil on your boot

05-11-2011, 11:49 AM	#9
Grider Pirate Beastly Adventurer Joined: Sep 2007 Location: LV, NV Oddometer: 1,669	The OTHER thread I think that kinda puts it back in the 'other' (pushrod tube in the head) http://www.advrider.com/forums/showthread.php?t=685835 thread area. A couple of the 'old wise ones' have commented that the tube pressed into the head can leak. I have less experience, so I've never seen that happen. I sure can't think of anywhere else your leak could be originating! (Okay, maybe the rocker cover center stud on the head side??? I kinda' don't think that can happen, but.......) __________________ Please don't tell Mom I'm a pilot. She thinks I play piano in a whorehouse. http://griderpirate.smugmug.com/ http://www.youtube.com/my_videos?feature=mhum

05-11-2011, 07:00 PM	#11
bmweuro Mad Scientist Joined: Nov 2003 Location: Chico, California Oddometer: 2,948	Going out on a limb here. On an old Boxer your foot is under the carburetor and the breather hose runs through the right air tube. If it's a high mileage motor maybe it's blow by leaking between the air tube and the carburetor. __________________ BOXER Metal BMW Biker Scum BMW Mad Scientist! VBMWMO #7770, BMW MOA #48694 & Airhead BMW Club #600

05-11-2011, 08:00 PM	#15
bmweuro Mad Scientist Joined: Nov 2003 Location: Chico, California Oddometer: 2,948	To rule all of this out pull the air tube and clean it out really well. Put it back on the bike and see if your still get oil on your boot __________________ BOXER Metal BMW Biker Scum BMW Mad Scientist! VBMWMO #7770, BMW MOA #48694 & Airhead BMW Club #600

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05-10-2011, 03:39 AM	#3
Horsehockey A GPS? Huh? Joined: Nov 2010 Location: Vermont Oddometer: 222	As noted above, you should clean the right side of the engine case of oil and dirt. Then spray the area with spray foot powder or baby powder. Then take it for a ride. The powder will expose the source of the leak. My guess is the oil is dripping off the bottom of the right side airtube and/or collecting on the bottom of the float bowl. Oil collects there because your crankcase breather sends oil mist to your right side carb via the tube and some of that oil leaks out at the bottom of the airtube where it mates with the carb. Entirely normal.

05-11-2011, 03:05 AM	#6
Horsehockey A GPS? Huh? Joined: Nov 2010 Location: Vermont Oddometer: 222	http://www.discountwholesaleonline.c...med/424598.jpg