oil in air filter box?!?!?

The story goes... I have an 82 xj650 and was having carb problems (RickCoMatic troubleshot for me), but I got the bike running. Unfortunately, just as I started to get the bike running well, it started acting up again. I put it away for the night and the next morning I came out and there was oil (I thought it was fuel at first) all over the ground. It seemed to be dripping from the rubber boot where the drive shaft connects into the engine. I tried to start the bike when I got home to see if I could troubleshoot where the fluid was coming from but it would not start. Taking the cover off the air filter box, I noticed a layer of oil inside.

What the heck is going on with this thing??? Does anyone have an idea where the fluid could be coming from? Im still not 100% sure it is engine oil. And most of all, why would there be oil in my air cleaner box? Im going to work on it again on sunday and I would like to know if there is a place better to start than another.

 

There is one thing I can think of as I had a similar problem. Did you do an oil change recently? The problem I had was I put in too much oil so it would overflow through the airbox (connected) and cause an even bigger problem of oil leaking in front of the rear tire, causing me to slip while riding (very bad lol) I remedied this problem by doing an oil change and getting rid of all that excess oil that I had put in (thought I was low) Hope this gives you an idea of where to start.

 

I did do an oil change a few months ago but I think this is more of a seal/gasket failure because there was A LOT of fluid on the ground. Would the overflow cause a leak from the rubber boot coming of the rear of the engine? The boot just seems to be a dusk/mud cover to protect the linkage of the drive shaft but I have not been able to dig in there yet.
I will surely look into the oil overflow. Thanks

 

The boot on the final drive ujoint is just a dust cover. It would have to be leaking from the inner oil seal if it is coming from there. Don't dismiss the oil overflow yet. If your petcock is leaking and the float valves are not sealing then the fuel will flow into the carbs, fill up there and then spill into the intake. From there it goes into the cylinder and down into the crankcase. When the engine is running the breather pipe will channel the excess fuel/oil mix ito the air box. That breather pipe is located on the left side of the engine to the back and top of the tranny cover. It runs from there to the airbox. It is there to allow the vacuum in the intake airbox to suck left over gases out of the crankcase. So if the oil level is high it can very easily suck that into the airbox.

 

That sound like a very real possibility because the fluid did smell like fuel but if felt like a diluted oil... So maybe it was a mixture of the two. The reason I originally thought it was fuel was because I had the petcock in the "PRI" position by mistake and the fuel level seemed to have gone down. Do you think I should drain what oil is left and start fresh? I tried looking through the glass at the bottom of the engine but the glass is too dark to see through, even with a flashlight.

If this was the case, then this would mean that my float valves are not seeling right? Could this have contributed to my carb problems (fowled plusg)?

 

I just looked at my air filter box and it had oil in it but I just did some clutch work and when I filled the bike back up I put too much oil in so I drained the oil and put only three qrts in insted of 4.5 qrts should I get a new filter because its filled with oil and fuel, and could I have messed up other things buy over filling the bike?

 

Great question Tonymyrs. I have the same one. Did I mess anything else up now that this happened? Im thinking no but you guys are the experts. I only get to work on it a couple times a month.

Last night I thought I would check and see if it was fuel dripping so I put the petcock back in PRI..... The verdict was YES. Fluid on the ground again and the fuel tank was lower. It still seems like oil is mixed in with it so Im going to drain the oil and fill back up to make sure I have the correct amount.

 

Did I mess anything up? No. Whether it be over filled by oil or fuel it won't really hurt the bike. It can get into the intake air stream path and cause rough running or clog the air filter somewhat. The fuel/oil mix doesn't hurt the engine either. Now if you keep that mix in there for an extended time it could. Just change the oil and filter and you should be good. In the event some oil got into your carbs you can always run some Seafoam through for that.
There was a discussion some time ago on the XJowners list about the fuel harming the engine due to thin oil. It was a standard practice to run aircraft engines with avgas in the oil to thin it our in actic conditions. This to keep the oil from freezing. So we a have practical experience of his condition in air cooled engnes. However it must be noted that most aircraft engines have a much lower redline. Somewhere around 3500 rpm. Compare that to our redline of 9K and ou are comparing apples to oranges.

 

Blue Max is right you probably didn't hurt that engine, but, run it like that in the hot summer or for an extended period of time and look out.

I personaly dont care for the ol vacuum petcock! I feel like if someone is so dumb that they can't remember to turn the fuel off and on then they probably have no business riding.
Yep, I have forgotten before, but it only takes a second to reach down and turn that baby back on.
I became habit on my other bikes in the past.
Now I'm lazy!?

Change yer oil and filter and you'll be ok. (provided you set the petcock right)

 

I changed my oil and sure enougth, it was like dumping out my gas tank. ... Nothing but fuel with some oil in it.

This means that my float valves are leaking by right? Would this cause my plugs to fowl while running? It seems to me that this would be too slow a leak to effect the engine while it is running. How do I fix this?

 

I had a similar issue, although fuel didn't run through on RES, just ON.

The parts guy at the stealership advised me to replace the disc in the valve body, and that solved the problem.

The disc is directly behind the fuel cock and you can get to it without removing the valve from the bike. Remove the two phillips screws that hold the retainer for the fuel cock on. The fuel cock will pull right out.

Behind it there is a circular rubber disc with 5 holes, one in the center and 4 evenly spaced radially around. There are raised bosses around each of the holes. The bosses provide the seal to the various passages. In my case the bosses were visibly worn away.

The disc was $8 at the stealership, vs about $30 for the rebuild kit.

When I had the carbs off the bike I removed the fuel bowls and inverted the carbs. By blowing on the fuel line I was able to hear the #3 needle valve leaking. I pulled the needle and the rubber tip looked pretty good, used a q-tip to clean the seat. Now it is tight. I'll probably replace the needles and seats next time I have the carbs off.

 

First thing to check is your petcock. Easily checked by removing the fuel line. If fuel leaks out then it needs replacing or repaired with a repair kit. To fix the carbs they have to be removed and the float valves replaced. The valves can be purchased seperately so you don't have the expense of 4 carb kits at $20 a piece. partsnmore.com has them for $4 a piece but they also have a $35 minium order. oldbikebarn.com has them for $9.95 a piece.

 

I am having the same problem with the oil in the filter box. its coming out of a tube that hooks to the bottom of the engine then directly into the filter holding box. when i try to turn it over oil spurts out into the air filter box. im not sure what to do! any suggestions?

 

Hi Tim and welcome.
First order of business, have you checked your oil level? Two possible causes of this oil in the airbox issue: over servicing the oil and one or more stuck carburetor fuel float valves. The fuel in the oil is easy to recognize, does the oil stink of fuel?
The first is an easy fix, drain the excess. The second will require a bit more work. You will need to pull the carbs, clean and/or replace the fuel valves and change your oil.

Just a quick note, check the forums using the search function on the left side of the page, you will find lots of hits for your symptoms.

 

back to the original issue for a sec, fuel in the oil. Just leaving the petcock on PRI or even having petcock issues alone will not cause the fuel in the oil syndrome...
The float valves have to be not shutting off as well. If your floats are all operating 100% correctly then they wouldn't allow the fuel out of the carbs to get into the crankcase.

 

Thanks for the welcome!

I cleaned the carbs up with some carb cleaner spray, but im not sure about the oil level. this is my first bike so im kinda new to this. the oil does seem to be a little watery, so it could have some gas in it. i will have to check it out when i get home from work. from what I have been reading it looks like it has too much oil. will i have to clean the carbs again?

 

if it suddenly got "too much oil" on its own then the carbs are letting fuel into the engine.

CLEANING may not be the entire issue; you may have a worn/failed or stuck float needle OR simply a float with the level WAAYY out of adjustment.

"Cleaning up with some spray" is NOT cleaning the carbs though. The rack needs to be removed and the carbs broken down at least partially to accomplish any sort of effective cleaning.

 

yep looks like my bike had waaaaaay too much oil in it. when i emptied it out, there was about a gallon there. no wonder oil was spitting into my air filter box.

 

With your Carbs approaching 25-years old ... I'd recommend that you "Dress" the Diaphragm Piston Bores.

Scrubbing them down to bare Aluminum and eliminating the Aluminum Oxide Tarnish they get over the ages will help to restore performance to the Carbs.