GL1100 crankcase breather hose constantly puking oil

[stuartdivebum]

Hi all
This is driving me nuts, I have a new to me 1981 GL 1100 it has a new 4 into 1 weber 20/22 carb and manifold with a small air cleaner the crankcase vent hose runs open to the atmosphere and it constantly blows oil out of the vent hose. Low speed or high speed
- The oil is fresh and not overfilled
- The bike runs great (except for puking oil all the time) no stumbles or hesitation
- passes compression test according to my local shop
- no head gasket leaks
The bike is practically unridable as it uses more oil than a two-stroke, anybody have any insight as to what the issue may be?
Thanks
Dave

[Oldboy]

Sounds like you have a lot of blow by.....poor ring seal. How do the plugs look?

[ericheath]

6A8445C1-DA74-4323-A251-1C7906599D5B.png (85.39 KiB) Viewed 296 times

Probably doesn’t help, but this how it’s supposed to work.

[flyin900]

Check it with your oil filler cap off and see if you are getting lots of pressure coming out of there too when the motor is running. It sounds like your crank case is being pressurized and that would be leaking rings (most likely) or valves guides allowing compression to leak into the crankcase.
Did the shop that did the compression test give you any numbers that they observed on the test?
If the bike sat for a long time before getting it running again, it is not unusual for the rings to be sticking. Usually after a 100 miles or so of riding they will loosen up and seal more completely.
If the latter is the case then you can introduce a pint of Seafoam into the oil and let the motor run at idle for 10 mins. with a fan on the rad if it is hot where you are and watching the temp gauge. After that drop the oil and change with fresh oil and again riding the bike over a distance will help release any sticking rings. The Seafoam will just help flush and remove any gummy residue from the rings and interior oil passages.

[stuartdivebum]

Sounds like you have a lot of blow by.....poor ring seal. How do the plugs look?

plugs look Ok, all four light tan color. Its the strangest thing, It runs really good except for its vent problem. I rode it about 125 miles this past weekend (picking it up) and the motor had blown out about a quart of oil you couldn't see oil in the sight window when the ride was done, it was full to the mark when I left. I hate to pull the motor down until I have no other option, the original miles odometer miles is 17614 the wing looks almost new, had set in storage for many years. A trusted friend got it running and did the single carb swap, we have done this carb mod on several older GLs with great results. I was thinking about routing crankcase vent hose directly into the air cleaner assy but fear it will overload carb with oil

[Whiskerfish]

I went through this with one of my engines a few years ago but mine would only do it under a load. It was a mid life engine between 120 and 130,000 miles but I think the real reason was it had been over heated. As a 78 the Crank breather feeds into the intake and it had been fouling the carbs for years and i could not figure out why. I put a new engine in it.

[flyin900]

Again check for high pressure in the crankcase. If your getting lots of pressure in there then there is a reason for that happening. Have you just got an open hose venting horizontally, or is there a small breather mounted on the end of the hose. Normally that hose would be vertical and connected directly into the air box
Some pressure from the crankcase is normal, yet if you have lots of pressure coming out of the crankcase then the above solution obviously won't help.
Here's a couple of pictures of the GL1100 stock air box that has a U shaped section that is actually sealed from the air filter section by the metal bottom of the filter. There is an input from the engine on one side of the bottom of the air box and and outlet on the other side to a drain hose.
Possibly this system offers some way of reducing the pressure and oil blow by on the motor?

P1060074.JPG (85.14 KiB) Viewed 270 times

P1060073.JPG (110.41 KiB) Viewed 270 times

[stuartdivebum]

Again check for high pressure in the crankcase. If your getting lots of pressure in there then there is a reason for that happening. Have you just got an open hose venting horizontally, or is there a small breather mounted on the end of the hose. Normally that hose would be vertical and connected directly into the air box
Some pressure from the crankcase is normal, yet if you have lots of pressure coming out of the crankcase then the above solution obviously won't help.
Here's a couple of pictures of the GL1100 stock air box that has a U shaped section that is actually sealed from the air filter section by the metal bottom of the filter. There is an input from the engine on one side of the bottom of the air box and and outlet on the other side to a drain hose.
Possibly this system offers some way of reducing the pressure and oil blow by on the motor?

P1060074.JPG
P1060073.JPG

- It vents vertically straight up by a K&N style airbox and is open to the atmosphere, no filter. I have tried a filter on the vent hose but it clogs up with oil within a few days
- at smooth idle, it vents some pressure out of the hose but no more it would seem than my GL1000, it really seems at its worse for venting oil at highway speeds
- I was thinking of maybe an oil catch can to give it a little resistance and trap some oil but not sure if that would do anything except spend money.
- it doesn't foul the plugs and she runs really well except for the oil venting issue
- If it was an HD I would say the oil pump breather gear was out of time but I don't think a GL oil pump works in the same manner

[flyin900]

You say it vents horizontally? Vertically is the way to go as in the stock set up and maybe that is what you mean? There is a plastic tank storage shown on the parts fiche for the 1981 GL1100 where the outlet hose from the bottom of the air box is connected.
Do you have the compression numbers on the cylinders from the shop? You want to see 150+ on a really healthy motor.
My only other thought is possibly the rings are still sticking from a long layup. I would think after a 100+ miles on your ride home they would have freed up, yet maybe not. If you have a favorite product you like such as Marvel Mystery Oil, Deep Creep etc it maybe worth running some as previously mentioned in post #4 to see if that helps.

[gltriker]

Hi all
This is driving me nuts, I have a new to me 1981 GL 1100 it has a new 4 into 1 weber 20/22 carb and manifold with a small air cleaner the crankcase vent hose runs open to the atmosphere and it constantly blows oil out of the vent hose. Low speed or high speed
- The oil is fresh and not overfilled I am not familiar with checking engine oil level on an 1100.
- The bike runs great (except for puking oil all the time) no stumbles or hesitation
- passes compression test according to my local shop no leakdown test performed?
- no head gasket leaks
The bike is practically unridable as it uses more oil than a two-stroke, anybody have any insight as to what the issue may be?
Thanks
Dave

If this was my engine I would:

#1 drain the engine oil and refill to the proper level.

#2 Perform an individual cylinders' leak down test.

[gltriker]

6A8445C1-DA74-4323-A251-1C7906599D5B.png

Probably doesn’t help, but this how it’s supposed to work.

Eric! I am not familiar with the internal details of this engine. But, the drawing vaguely indicates the crankcase vapor is
following a cavity upwards towards the breather fitting?

Is there supposed to be some sort of baffling in the crankcase vapor path that prevents slung off engine oil from directly reaching the underside of the breather hose fitting?

The crankshaft would be most responsible for engine oil sling off?
(Respectfully, I suspect the engine crankcase is overfilled and the underside of the 4 pistons are, collectively, aggressively agitating the liquid oil level.)

[stuartdivebum]

Yes I meant vertical, long day. I am gonna try the deep creep/MMO and then go for a 100-200 mile ride this coming weekend and see if the oil issue abates. If not I have a spare motor or I will go into this one and see what’s up

[robin1731]

I can't agree with adding deep creep to an engine and then running it. Even worse riding it. Maybe some sea foam or atf but nothing else. Just riding the bike normally without adding anything will loosen up stuck rings from sitting. As has been said earlier make absolutely sure it isn't over filled. That much oil in that short of time sort of points to that.

Also, like gltriker said I was thinking of a leakdown test. Any shop that didn't do that with this issue after doing compression check is subject IMO.

[CYBORG]

Hi all
This is driving me nuts, I have a new to me 1981 GL 1100 it has a new 4 into 1 weber 20/22 carb and manifold with a small air cleaner the crankcase vent hose runs open to the atmosphere and it constantly blows oil out of the vent hose. Low speed or high speed
- The oil is fresh and not overfilled
- The bike runs great (except for puking oil all the time) no stumbles or hesitation
- passes compression test according to my local shop
- no head gasket leaks
The bike is practically unridable as it uses more oil than a two-stroke, anybody have any insight as to what the issue may be?
Thanks
Dave

Not really enough information here to give an opinion. You say the oil is full. To the top line? to the lower line? in the middle? What are the compression numbers? How is the vent hose routed. Just to name a few. What type and weight of oil are you using?

[robin1731]

Hi all
This is driving me nuts, I have a new to me 1981 GL 1100 it has a new 4 into 1 weber 20/22 carb and manifold with a small air cleaner the crankcase vent hose runs open to the atmosphere and it constantly blows oil out of the vent hose. Low speed or high speed
- The oil is fresh and not overfilled
- The bike runs great (except for puking oil all the time) no stumbles or hesitation
- passes compression test according to my local shop
- no head gasket leaks
The bike is practically unridable as it uses more oil than a two-stroke, anybody have any insight as to what the issue may be?
Thanks
Dave

Not really enough information here to give an opinion. You say the oil is full. To the top line? to the lower line? in the middle? What are the compression numbers? How is the vent hose routed. Just to name a few. What type and weight of oil are you using?

Checked with the bike on the center stand.

.