Leaking oil and gas when running.

[James Terrell]

I have this 79 xs 1100. I got a really good deal on it and it's leaking oil and gas out of the air filter. Out a hole on the bottom of it. Why does oil go into the air filter in the first place. Does this hole on the air filter suppose to have a hose running from it back into the crankcase? Please help with this. I was told that my carbs are out of sink. ? I already fixed the petcocks. Those are working perfect now.

[knewsom]

James,

Welcome, and good luck with your ride!


First things first, make sure you check your oil for gas - if it's leaking out your air filter, it's possible that it's been leaking into the crankcase as well. Dip in a stick, get some oil on it, and hold it over a flame. if the oil lights easily, then there's gas in it, and it's gotta be changed. Before you do change it, you may want to drain your carbs, and remove them from the bike for maintenance, because it's gonna need it.

Your airbox shouldn't be leaking oil. AT ALL. unless of course, there's a K&N filter in the box, and the gasoline has gotten some oil in it from the oil on the filter and THEN run out of the box. Other scenario is (as far as I can tell) that oil is being pushed into your airbox from your crankcase vent?? you may also want to check your oil level to make sure some jackaz didn't overfill it.

Now once you've got your carbs off, you'll need to disassemble them as per the tech tips, becuase I'd be willing to bet you have bad float valves/seats and probably bad floats as well. It's possible everything is just all gummed up and that a good cleaning will suffice, but it's really hard to say. Get it apart, take a look at the bits inside, maybe replace the float valves, seats and floats after a good solid cleaning of the carbs, in general, and give it a try again.

Best of luck again... and don't be overwhelmed! Before you do something it seems really tough, but then once you've done it, the ususal feeling is one of "oh. wait, that's it..?? what the heck have I been paying a mechanic for all these years!?"

-Kris

[Ken Talbot]

Oil coming out of the airbox vent could be from a grossly overfilled crankcase. This happenned to me whan I bought Tsunami from a guy who never actually rode it or got to know about is from the guy he bought it from. He didn't know how to check the oil level with the sight glass on the right side, so just filled it to the bottom of the filler hole like you would do with an old Briggs and Stratton.

To diagnose the problem of gas coming out of the airbox, we need to know more detail about exactly which model of XS you have. Without a doubt, you have at least one float valve that is not sealing. If you have a Standard, you also have at least one petcock that is not shutting off properly. If you have a special, the "octopus" fuel diaphragm is not shutting off properly.

The drain hole is not supposed to have a hose.