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I had posted a problem earlier, oil pouring out of a hose on the bottom of my bike. I followed the hose up to my airbox and opened it to find a mixture of oil and gas inside. What am I looking at here? The bikes an 83 gs750es. I also checked and think there may be a hint of gas in the crankcase. i really don't have a clue about motors and am not sure where to start.
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Gas in your airbox means your carbs are flooding. Multiple reasons for that, starting with your rubber tubes (boots) may have a pinhole/crack. The rubber gets brittle with age. It's a common problem. I've heard it said you could spray WD40 at them while running. If the idle speed increases, you've got an air-leak... Mostly, the carbs should be removed and cleaned, checking for wear on the needles/seats. Check float height, etc...
Oil in the airbox. You have a rubber tube coming off the valve cover to the airbox, so you can reburn the fumes. This is where the oil is coming from. I have no idea why the oil is travelling through there, but it isn't a good sign. Somebody else may know why that is... -
Good answers, Robben.
One other possibility for oil in the airbox is if the foam air filter has been over-oiled, leading to the excess oil draining down onto the floor of the airbox. You should be able to tell which is the source of the oil (air filter or valve cover tube) by visual inspection.
BBComment
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Ahhh, never thought of that. My airboxes use(d) paper air filters... 
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Thanks, guys. Now i know where to start lookingComment
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I just reread your first post and noticed I missed that bit about a hint of gas in the crankcase... 8O Definitely got some sort of flooding going on.
Make sure your petcock is working properly, too. If the carbs are flooding, and your petcock is not shutting the flow off, you can end up draining your whole tank into the crankcase. Not a good thing, for sure.
Not familiar with your setup. Is it a vacuum switch or is there an off setting? You'd know if it was a vacuum as it has two lines going to it, one's fuel and the other's the vacuum line, and the settings are RES, ON, PRI.
If there's just a hint of gas in the oil, it's probably just draining the fuel line's worth of gas itself and the petcock's fine.
Good luck, bro'.Comment
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Could you have a blocked engine breather? And your cases are pressurised forcing a little oil into the airbox?Comment
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Also, you're petcock is a vacuum type, where the engine will "suck" fuel into the carbs upon starting. Try starting the bike with the petcock set in the "ON" position.
If you have fuel in your crankcase oil, CHANGE YOUR OIL. The fuel will thin the oil, not good.
Brad ttComment
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Oooh, that would make sense. Those foam filters in the breather cover get really nasty over time.Could you have a blocked engine breather? And your cases are pressurised forcing a little oil into the airbox?Currently bikeless
'81 GS 1100EX - "Peace, by superior fire power."
'06 FZ1000 - "What we are dealing with here, is a COMPLETE lack of respect for the law."
I ride, therefore I am.... constantly buying new tires.
"Tell me what kind of an accident you are going to have, and I will tell you which helmet to wear." - Harry HurtComment
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The engine breather was mentioned, I know nothing about engines so where could I find this breather?! I know it's sad but that's why I ask. Thanks again for help.Comment
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You've got the same bike as Simon (BB) and myself.
The breather filter has a rectangular cover that sit's right on top of your vavle cover. It's where the Breather hose connects too.
edit: Fun as H$ll bike, if I don't say so myself. 8)Comment
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Thanks again guys hopefully I'll have time to get it apart tommorow.
Ok I had seen that and thought that could be it.
Well thanks again, I'm sure this won't be the last you here from meComment
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