strange fuel leak?

Hey Guys... have an '86 XJ700. Don't ride it much and stays in garage. Had a new head put on, carbs cleaned adjusted, etc. about a year ago but have not really put any miles on it. I have not had a chance to really look it over well (always gone trucking) but here's the basic problem. Took it out of the garage 2 weeks ago, siphoned old gas out, and refilled with fresh Shell regular and couple ounzes of Sta-bil. Left it outside garage for 3 days. Got ready to bring it back in, it started but was running rough and had gas leaking on the ground real bad. Shut it off and could not find anything wet from the petcock on down to the bottom of the cylinders. Tried starting again and noticed that gas was leaking real fast and right onto the exhaust pipe so shut it off and set it in the garage for the nite. Next morning it was still dripping so set it back outside. now comes the odd part...... noticed the gas was running out from inside the driveshaft boot and was all wet inside boot. It was gas and evaporated after leaking on the driveway. Put it back in the garage and took off trucking for 5 days. When I got back, I noticed the garage floor was all wet and not evaporated. When I felt of it, it felt like motor oil mixed with gas. What in the world happened?!! Did the gas leak into the carbs, thru the heads, into the cylindars and into the lower case to mix with the oil? Like I said, haven't had the time to really check it out..... but this doesn't feel good. Tks gang....... Gil :?

 

Your carb floats are stuck open and overflowing into the engine. You might be able to free them by tapping on the carb rack with the plastic end of a big screwdriver or rubber mallet. If that does not work then removing the carbs is necessary. Be sure to change the oil and filter. Don't let your bike sit that long, start it up every few weeks and ride it. Keeping the fluids circulating will prevent this from happening again.

 

I agree with mlew.

Pull the carbs and give them a good once over. Make all the adjustments and sync when your done. If the bike is going to sit for any length of time. use your float bowl drains and get the fuel out of the carbs so they don't crud up again.

MN

 

Yep, my guess as well. You need to drain it all,pull the carbs
and check the floats.
I was OTR for a while and know the limits on time...thats why
I stay local lol.
But your prob started when the carbs over-flowed-there are passages
for that on the carbs-but then drained into the case.
So, all is fixable,you just need to figure out if it's the float
or the petcock thats causing the fuel to flow.

 

Unless you've left it on PRI, chances are it's a stuck float.

It probably didn't get into the gas and then fill the driveline up, more likely it puked all over the top of everything and got into the final drive boot that way.

 

Might as well check your petcok vacuum shutoff if it has one. Not sure about an 86 model. If you left the petcok on for this then something's wrong with it. Maybe bad or stuck diaphram/o-ring. Obtw the guys are right. floats are sticky too.

 

Weezil51's problem more or less matches mine.

Started my very rarely used '84 XJ-900, it coughed & spluttered then died before I could take off.

I looked down and saw fuel (that seemed oily to me) gushing out onto the ground.

With the motor & ignition now off, it continued to come out, had to be way more than the contents of an carby'.

Now here's where I flaunt my lack of mechanical knowledge; behind the carby's is a large black plastic structure which I would have called the manifold, but now understand it to be the airbox. The fuel appeared to be flowing out of a hole in the bottom of the box, but once the driveway was fairly flooded (the leaking had stopped), as far as I could see with limited visibility, it looks like the hole was a small manufactured one (a drain hole for just such a problem?).

Does my sad tale match up with the same likely diagnosis - stuck carb floats, and would there indeed have been engine oil in the spill?

Thanks in anticipation of any advice.

PS. Just on the off chance .... anyone know a good XJ mechanic in Brisbane Australia?

 

Sounds like another case of stuck floats and dirty carbs.

MN

 

Couldn't agree more with the advice given, but make sure you go one step further and check your needle valves as well. The floats my be operating correctly, but the rubber tips on the needle valves could be deteriorating. If those are anything less than perfect, they'll leak.

 

Yes and yes. The airbox has a drain hole or holes, and the way it includes oil is the gas gets into the crankcase causing the "oil" (now gas and oil) level to rise. When you run the motor this mixture will pump out the breather into the airbox, fouling your air filter and dumping the mix all over the place.

Because the intake tract is essentially "downhill" the carbs don't generally flood directly into the airbox.

You should change your oil right away as well.

 

Thanks MN-Maxims, andrewlong and bigfitz52.

Obviously, the bike needs some serious (though I figure, not economically unviable) work.

As well as knowing that my beloved XJ900 is not cactus, I can now approach a local mechanic in a position of being if not knowledgeable, at least, educated.

Again, thanks for the responses, prompt as it was at that.