Rising Oil Level?

[gbw]

Greetings all you smart GSers out there. I have a question about the oil level in my 77 GS750B. Wonder if anyone has any info on this. First the story then the question.

Back in late October 07 when I checking this bike trying to decide if this was the bike for me, one of the first things I did was check the oil level. The oil was very dark but was clearly between the L and F marks on the glass. At some point after I bought it I noticed that the oil level was well above the F. The oil level was so high that the window was completely black.

After reading some posts here I figured that my petcock was bad and that I was getting fuel in the crankcase. But, before I just buy a new petcock I wanted to be sure. I decided the change the oil and see what was what, which I finally did on Tuesday (3/25).

Got the old black oil all drained out, put in a new filter, and got some good clean 10w40 back in there. Hit the glass just between the L and F marks.

Now this new 10w40 came in a one gallon jug and I used just about the whole thing to get the right level I poured the remaining pint or so into a tupperware container to save for later use and put the old black oil in the gallon jug. Funny thing about the old oil. It does not smell like fuel and there is only about 4 quarts of it. Boy did that make me feel good. No $60 petcock required.

Anyway, I've been riding a little since then. 60 or 70 miles each a couple of times this week and a few hours today. Each time I check the oil level, tire pressure, etc before I leave. Everything is A-OK. I get home from a little grocery run tonight, decide to oil the chain, and while I'm doing that I see a can of Seafoam. I realize that I had forgotten the part of my oil change plan which included adding Seafoam to the crankcase.

So, as I'm about the put the Seafoam in and I notice that my oil level is above the F mark. So far above the mark that all I can see in the glass is oil.

I'm at a loss. How can this be? BTW, I did not add the Seafoam. I'm not sure what to do now. Do I drain some oil out? How could it have gone up? Where would it come from?

Any ideas, advise, suggestions?

Thanks,
gbw

[bwringer]

You need a new petcock.

There are only two fluids in an air-cooled motorcycle -- gas and oil. One is getting into the other.

[tomcat24551]

If there's oil in the gas, you should be able to smell it when when you take off the filler cap. No smell, probably no gas.

I never fill my 850 higher than the "L" mark initially. I have noticed that many times the oil level will rise when the engine gets full hot. That's when I top it off --if it needs it.

Tomcat

[Nessism]

It's normal for the oil level to increase as oil drains back into the crankcase. When filling the oil after an oil change I usually aim for the middle of the fill range, checking the level with the bike on the centerstand and about 1 min. after turning off the bike. After about 10 min. of sitting the oil level increases - to near the H mark.

All this said, you should do some checking to make sure your petcock is working properly.

Good luck.

[lurch12_2000]

I assume you're measuring with the bike on the centerstand and on level ground?
If I tilt my bike back slightly on the centerstand it will show higher (at Full mark) whereas if it sitting normally with weight forward it will read down close to the Low mark.
So if I normally fill the oil to the F mark and I tilt the bike back(such as put weight on my luggage rack) a little it will fill the whole window.

[chef1366]

Burnt oil + fuel smells like burnt oil. If you pulled four quarts out of the bike more than likely you need a petcock and new float needles and seats. (But you can get away with just a petcock)

[tone]

as above if the level was checked correctly the first time round & now its risen the fuel tap is passing fuel throught the carbs & into the crankcases

you didnt leave it on prime did you ? (if it has one)

[tkent02]

Petcock test...

Easy test, see if fuel comes out when it's not running. Hook a hose to the fuel outlet, no fuel should flow unless a vacuum is pulled on the other little hose...

More comprehensive test, make the hose long enough to reach a jar on the ground, start fuel flowing using PRI then turn it off leaving the hose completely full of fuel.

This uses the principle of a syphon to suck fuel down the hose, will put fuel through unless the petcock is really sealing tight.

If no fuel has come through the line after a few hours your petcock is good, assuming it flows enough fuel when it is supposed to.

[Bizcocho]

My bad petcock shut off ok, so if I understand the above test it would have passed it. But gas was being sucked through a pinhole in the diaphragm and into the engine - and into the oil. I put a LONG transparent tube on the vacuum attachment to the petcock and sucked on it. As soon as I saw gas in the tube I know I had a problem. LONG so I wouldn't suck gas into my lungs by mistake. A vacuum pump is better still.

~Rich

[fnickel]

Rising oil level

I actually did have the petcock problem, with fuel running into the crankcase. If you take the oil filler cap off the crankcase, you will definitely smell the gas in the crankcase if that is happening. The only other thing I can think of is to make sure the bike is level when you check the oil.

[gbw]

thank you!!!!

Really appreciate all the replies. A couple of comments:

1. I am checking the level on level ground with the bike on the center stand.

2. It is hard for me to tell if the oil smells like gas. The oil in there now is fresh and it might smell like gas, but then again, my noise is right there under the carbs and they always smell like gas a little. I think one might have a little leak. Sometimes I smell gas when I'm riding...or it might be chain lube on the exhaust...I don't know.

3. I suspected that if I'm getting fuel in the oil it is via the vacuum line, but can't prove it. The various petcock positions seem to function properly but I can't tell if gas is going thru the vacuum line. I was going to install a clear line to check but decided to take a more aggressive approach.

What I've decided to do is this:

1. I'm going to go thru the whole bike just like the folks here recommend: Valve clearance, carb rebuild, petcock replacement, check all the electrical, etc. That should eliminate any issues and I hope it will only take a few weeks. The weather around here is supposed to be getting nice soon. I'd rather ride it than work on it, but I hate to ride it if I'm getting fuel in the oil. That can't be good for it. Plus, I've only owned the bike since November of last year so it will increase my piece of mind if I can do all of this and know it is right.

2. It is finally almost warm enough to work in the garage. I pulled the cars out today, put the bike front and center, set up a work bench, and installed 6 new florescent lights so I can see what I'm doing.

As I've been reading a lot of posts about folks who have done this I picked up a few things. One of which is that I cleaned the engine and the bike before I did anything. I pulled the tank and seat off today and I'm ready to start checking valve clearances tomorrow.

I've got a few pics that I will post and I'll post more as I go if you are interested. Suggestions are welcome and I'm sure I'll be burning up the search tool and asking questions as I go.

I don't think I would have the confidence to start this without the GS Resources Forum. This is a very special place. Thank you to those who created this and to those who support it. I hope as my own experience increases I will be able to add to the group more than take, but I'm afraid right now I'm more of a sponge than a source.

A few more questions for those who have read down this far (sorry for my long winded posts).

1. As I go thru this and have questions or post my experiences, should I post them in this same thread or start new threads as I go?

2. I think I have all the tools I need for the valve clearance work. But, once I get carbs done and back on the bike I'll need a sync tool. I'm not opposed to buying one (they look very cool) but I'm wondering if anyone in ChicagoLand would rent or loan me one.

3. I've been reading several threads on carb sync and some of them talk about running the bike at various throttle positions (1/4, 1/2, 3/4, full) then cutting (or chopping) the engine, pulling in the clutch, stopping, and checking the color of the plugs to fine-tune the mixture of the various jets. I've also read about something called ColorTune. Does using a ColorTune eliminate the need for this chopping procedure? If so I wouldn't mind owning one, but again if someone local has one for rent for loan I'd be interested in knowing about it.

Sorry for the super long post. This is almost half as long as BassCliff's most recent welcome message (but not as useful). You can probably tell that I'm a little nervous about starting this, but by this time tomorrow I'll be up to my elbows in it and beyond the point of no return...so here I go...

gbw