Oil in Airbox

I have read about this in other entries and am not sure I understand. So, I bring it to you all for help. Here is what happened. I finished working on my bike a few months ago and took it for a spin. When coming back from around the block, oil was pouring out of my airbox. I believe I had overfilled; however, I think my petcock was going bad.

I ordered a new/used petcock, put it in, cleaned the carbs, cleaned the airbox, put new oil and filter. Tried to start the bike. Even turning it over caused oil to pour out of the airbox. I haven't even got is started. Ideas?

 

I believe the breather pipe comes from the engine into the airbox to burn this crankcase pressure to make the bike a bit more environmentally friendly. Oil in the airbox can be caused by:

An overfull engine (The air bubble at the top of the oil inspection window should just be visible with the bike on the centrestand)

Oil contaminated with petrol because the vacuum tap lets fuel by AND the carburettor float needles are not sealing - note you need BOTH faults for this to happen.

Worn piston rings - which pressurise the crankcase and push the oil out. This tends to be on high mileage engines and you should be able to see the oil being burned as you ride (Blue smoke)- because oil moves past the rings and is burnt.

I would favour option 1!!

 

I am not liking the sound of this.

1) Since I just put 3 quarts of oil in the bike, I don't think its that problem.

2) I only cranked the engine for about 1 minute and I put on a new/used petcock. I don't think too much fuel could have gotten in.

I hope it isn't piston rings. This makes me sell the bike as a parts bike. Don't think I want to get that deep. Not happy.

 

i just thought of something did you clean out your airbox if not i could be just working its way to the bottom. 2nd is your air filter clean probably not it but if im correct the hose hooks on on the inside of the air intake if the filter is clogging up needs to get air from somewhere just a thought

 

It's one of those foam filters. I will remove it and see if it still happens. Will let you know.

 

1) Yep I can see the top of the oil.

2) The bike says 25,000. This is in question.

3) LOADS OF OIL. POURING OUT. it was a nasty scene.

Went out to try without the air filter in and the blankety blank blank battery needed charged. If it ain't one thing it is the tother. Guess I will try and test without the filter tomorrow.

 

pull the crankcase breather tube. If you have oil coming from the tube then youve eliminated oil from the airbox.

If it is coming from there you've got blowby or maybe theres an oil deflector or something gone arye.

PM Bigfitz he might be able to help.

 

You might collect a sample of the oil that's coming out and inspect it. If it hints of gasolene then you have the material that's overflowing. Since you can see the top of the oil in the window though this probably isn't likely to be the cause. Still though I'd check the sample and see if the viscosity is less than that of new oil & if it smells of gas.

When I got my 650 Maxim running, I had large amounts of oil coming out the same as you are experiencing. My oil was way too thin, smelled like gas and when I put a match to a little bit of it, it took off instantly and I knew it was gas. I had to rebuild the petcock and I did buy a complete carb rebuild kit from Chacal and that resolved the problem completely.

If you're not getting contaminated oil, you're experiencing a different problem.

 

Thanks everybody. One question. What is the crankcase breather tube?

 

it's a tube on the left rear of the engine and goes up to the airbox.

 

Did this thing puke oil before the oil change?
I've had oil in the airbox from bad valve stem seals but you are speaking of volume and that smells of over-servicing or cracked rings.
I would also jump on the wagon with the gang and check the oil for fuel. These bikes have a habit of suffering with hanging fuel float valves (from sitting and lack of service) that will fill the crankcase pretty darn quick.
Let's hope it is something simple.

 

OK... Here is what I did. I bought a new battery. The engine turned over like a champ. Then oil started flying out of the crackcase breather tube. The oil was very thin and like brown gravy.

Yes it sounds like lots of gas may be in my oil. The oil came out with no gas when I cranked it a couple of days ago. This was right after I got the whole thing back together.

So... what first.

Sounds like I need a in-line fuel shutoff for the petcock and a rebuild kit for my carbs. Sound right to anyone else?

 

If you shut off the fuel when the bike is not running, then you won't have to worry about the sticking float valve(s).

They may well start sealing as you use the bike.

 

Markie, That would be a great work-around. Does everyone agree with that. If I change the oil put in a shutoff valve and make sure it is turned off when I turn off the engine, it will be a work-around to my problem. True?

 

OK, I feel really really stupid but I have to ask this. I had just changed the oil when I first cranked it. I cranked it for about 3 minutes and the oild came up. Clean and I think with no fuel. Fuel floats on oil right. So why would I get clean oil from the crankcase hose? Was there enough time to get the fuel into the crankcase?

When I unplug the fuel line from the petcock, it doesn't seem to be leaking. I am just really confused. I don't get what is happening. Can anyone give me a good idea of what they think might be going on and the easiest way to fix it. I will try things one at a time.

 

Fuel does not float on oil, it will mix.
Fresh oil out of the crankcase hose suggests high pressure in the crankcase. This is possible cracked rings or really bad valve seals.
You need to do a compression test.

 

Thanks to everyone and all the information will be very helpful in the future. I have learned so much. Now for the admission of stupidity.

I thought I saw an air bubble. I didn't. I had my son do the filter change. When he did, he did not open the oil drain plug. In other words, I put oil on top of oil. Figured it out while laying in bed last night. It had over 4 liters of oil ... lol.. no wonder it was spitting it out.

As I said in my last post, I feel really stupid. Thanks for all of you who knew my oil was too high and didn't scream at me

Rode it this morning. Nice to be riding again.

 

Don't worry - we all do daft things! The best bike story I can remember was when I was 16 and went round a friends house to find he had just come home from hospital. he had cut his hand pretty badly with his Swiss army knife.

I asked him what he was doing. He replied "Fitting new grips to my bike. The rubber bits cut off ok but underneath was this hard plastic. I was trying to cut through it and the knife slipped and went into my hand."

"That bits supposed to be there.........." said I, "It makes the throttle work!"

 

Funny. It is true. I just hate when it happens to me . Stay tuned I may be about to start another one.

 

never trust a kid to actually want to do something and learn something