Oil in the air box.

[GS750GUY]

To check the petcock, pull off the vacuum line and see if gas comes out, or better yet, replace the vacuum line with clear tubing and run the bike to see if it fills with gas.
You might alwo want to run the bike around with the breather line into a catch can of some sort to see if you are blowing oil out the breather. 6 oz. of oil is a crazy amount of consumption. What do the plugs look like? They would be pitch black and there would be a trail of blue smoke in order to burn that much oil.

Thanks for your response Nessism!
I'm just now reading your response so I've not had a chance to look at plugs or do anything else yet, but I can tell you what I did discover.
The other day I was getting the bike out for a ride when I noticed what looked like oil laying on top of and running down the side of the crankcase. Upon further investigation I discovered the oil was dripping from underneath the airbox. When I pulled the side covers off the airbox I found oil pooling in the bottom recesses of the air box. And when I put the bike on its side stand evidently there was enough oil in the bottom of the airbox that it ran to the left side and was leaking out around the bottom of the left side cover and dripping onto the crankcase.

Evidently the hose that comes off the bottom of the breather must have been plugged because when I blew back through it the hose then cleared itself and allowed some of the oil to drip out the hose.

I welcome your insights and further thoughts regarding this.

Thanks again!

GS750Guy

[DimitriT]

Evidently the hose that comes off the bottom of the breather must have been plugged because when I blew back through it the hose then cleared itself and allowed some of the oil to drip out the hose.

Do you mean the hose that comes out of the bottom of the airbox?
There should be a hose which comes off the top of the valve cover
to the top of the airbox. This is the "breather" hose and allows
the engine to suck back any crankcase vapors.

But some oil might come along for the ride and this ends up in the
bottom of the airbox.

The airbox then has a hose which allows this oil to drip away. If this
hole gets plugged up the oil will accumulate in the airbox and eventually
find another way out.

Hope some of this helps

[GS750GUY]

Sudden excessive oil consumption.

So, I'm hearing that several possibilities regarding my oil consumption problem could be from either one, or a combination of the following:

• Stuck piston ring.
• Bad valve guide seals.
• Faulty petcock vacuum port.

Question regarding stuck piston ring:
If it were a stuck piston ring...why would this symptom show up now after I put 3000 miles on the bike? The bike did sit idle for about 5 years prior to my partial restoration. I just completed my third riding season after restoring the bike and during the first two riding seasons I went the entire season without the need to add a drop to the crankcase the whole season. I would think if it were a stuck ring it would have made itself known immediately when I started riding the bike.
Wouldn't that also be the case with valve guide seals? Wouldn't a person think that you would see a slow and gradgual use of oil rather than a sudden and grossly high level of oil consumption?

Also, I believe with car engines, I have seen products that you can put in car engines to free up sticky piston rings.
During the winter storage season, is there something I could possibly pour in each cylinder through the spark plug hole and let it sit all winter that might free up sticky rings?

Regarding a faulty petcock vacuum port:
How does this cause excessive oil consumption? I'm trying to wrap my head around how this works.

I'm thinking if the vacuum port on the petcock could cause a sudden and gross loss of oil that it would most likely be the culprit.

You can probably tell, there is a lot I don't know about engines.

Thanks!

GS750GUY

[rustybronco]

Put bike on center stand and top the oil off until it's at the full line. mark the floor where the bike is (with tape! not like a dog...) leave it set for 10-15 minutes and re-check the oil level.

clean air box of any oil residue.

go for a nice long enjoyable ride. (you may want to have someone follow you, looking for oil being burnt)

park the bike in the same spot. after setting of 30 minutes, does the oil level read the same as before? if it doesn't read the same, did you notice any blue smoke emanating out while you were riding?

check for oil in air box...

[Nessism]

A leaking petcock won’t cause oil consumption, but it could cause you to get lots of oily/fuel residue inside the airbox from excessive fogging out of the breather on top of the valve cover, which is how this thread started out I believe.

If I were you I’d do as Dale suggests, carefully measure the oil level and then take a ride to see what happens. Understand that oil expands when it’s hot so take that into account. If the engine is burning a lot of oil the spark plugs will be black and wet, plus there will be blue smoke. Stuck rings can be freed up sometimes using Marvel Mystery Oil in the cylinders, or in the gas, so you might want to try that if the engine is actually burning oil like suspected. Considering the low engine mileage, old valve guide seals seem like a more likely reason for the problem. Checking engine compression would be a good thing since it will give you some idea about the ring condition.

Good luck.

[2BRacing]

On the 850 there is wire mesh in the breather cover on top of the valve cover that helps to prevent oil drops going into the breather pipe to the airbox. Not sure if 750 also has this wire mesh, but maybe yours has been removed?

[GS750GUY]

On the 850 there is wire mesh in the breather cover on top of the valve cover that helps to prevent oil drops going into the breather pipe to the airbox. Not sure if 750 also has this wire mesh, but maybe yours has been removed?

Yes, my 750 has this wire mesh as well, and it is in place.
Thanks for the tip.
GS750GUY

[GS750GUY]

Stuck rings can be freed up sometimes using Marvel Mystery Oil in the cylinders, or in the gas, so you might want to try that if the engine is actually burning oil like suspected.
Good luck.[/QUOTE]

Do you suppose it would be alright to pour some Marvel Mystery Oil into each cylinder, slowly turn the engine over a few times with the kick start, and let it sit all winter? Would that hurt anything by doing that? I would just need to be sure I drain and change the oil and filter like I normally do next spring.
Has anyone had any luck freeing up sticky rings this way?

GS750GUY

[rustybronco]

Has anyone had any luck freeing up sticky rings...

GM Top Engine Cleaner.
pour some in the fuel tank and ride the snot out of it.

[GS750GUY]

GM Top Engine Cleaner.
pour some in the fuel tank and ride the snot out of it.

Thanks Rustybronco!!

Do I have to buy this from a GM distributor, or can I get it from any auto parts store?

GS750GUY

[rustybronco]

Your friendly GM dealer...

my departed ex- father-in-law* was a service manager at Buick dealer many, many moons ago. He used and swore by the stuff. that man knew his stuff, unlike most of the ones I see today.

I've used it both as a pour in the carb combustion chamber cleaner and used it as a fuel system/top end cleaner, when I used it way back when.
it was very good stuff. (coming from a person who works at a Ford dealer)

*wishing He was still around...

[rustybronco]

You might try this product. (I have never used it!)

http://www.saturnfans.com/forums/showthread.php?t=65966

procedure - 1 Internal Engine Cleaning

1. Warm up to normal operating temperature.

Important

In order for the cleaner to be effective, the engine must be warm.
2. Disconnect negative battery cable.
3. Remove spark plugs.
5. Pour 3 ounces of GM Piston and Ring Cleaner (P/N 12378549 12 ounce bottle) into each cylinder through the spark plug hole.
6. Cover the cylinder head and spark plug holes to prevent debris from getting into the combustion chamber and to prevent excess evaporation of the cleaner.
7. Allow the engine cleaner to soak for a minimum of 2 hours.

Notice

After the minimum 2-hour soak, there may be some cleaner left in the combustion chambers. Do not start the engine until all of the cleaner has been removed from the combustion chamber or severe engine damage may occur.
8. After the minimum 2-hour soak, remove the remaining cleaner from the combustion chambers by placing shop towels over all of the spark plug holes and cranking the engine through a few revolutions.
9. Install the spark plugs and spark plug wires.
10. Start the engine and run only enough to reach normal operating temperature.
11. Drain the engine oil and remove oil filter.
12. Install new oil filter.

I was trying to see the best way of removing the GM "P & R cleaner" and ripped this off from another site...

***After a 2-hour soak, you will vacuum the cleaner from the engine...***

***note, the stuff is probably flammable***

so be very careful with it!!!! and it may EAT paint!!!!!!!

[Nessism]

Those early Saturn engines had a problem with piston rings getting carboned up. An engineer that worked at the factory told me they recommend MMO in the gas tank to help free them up. That soaking technique is more of an immediate fix, or attempt to fix anyway. Worth a try.

[GS750GUY]

Thanks guys!! I'm going to give this method a shot. It's worth a try to fix the situation this way vs tearing into the engine.

Another thing I used to do with cars with sticky rings or valves was take the breather off the carb, warm up and rev the engine and pour an entire quart bottle of kerosene lamp fuel as fast as you can down the carb to where it almost stalls out and keep doing that until the bottle is empty.
This stuff is cheap, (back then less than a couple bucks a bottle) and comes in plastic bottles in places like WallMart where the keep housewares and the decrotive kerosene lamps. It even comes in scented aromas in different colors or non-scented clear.
I always did this at night because it would literally fog up the entire neighborhood with a heavy dense cloud of smoke.
It worked really well and made the whole neighborhood smell like vanilla.
I have a 5 gallon take on my GS750. I might try dumping a whole quart of it in the gas tank and top it off with 4 gallons of gas and like you say...take it out and run the snot out of it.

GS750GUY